What is the role of the Three Persons of the Godhead in creation?

Father, Son, and Holy Spirit constitute the Godhead. The "us" is these three in agreement about the decision to make man. (They are in agreement about everything; complete unity.) Also consider the Hebrew, which renders the term Elohim when referencing God in the text. It is considered to be plural in number, consisted with the triune nature of God, 3 persons, one God. In Isaiah 44:24 God (Specifically YHWH in the Hebrew, the Father) names Himself as the creator of all things, and the book of Colossians speaks of Christ as the creator and sustainer of all things. Are these contradictions? No. In effect, God created all things. Both the Father and Christ are God, and the Holy Spirit as well. In Acts 5:3-4, Paul told Ananais that he had lied to the Holy Spirit, and then turned around and said he lied to God, using Holy Spirit and God synonymously. (There are many scriptures that prove that the Holy Spirit is God, that is the most commonly used one because it's just a matter of following simple grammar rules to make the connection.)

Isaiah 44:24 "This is what the LORD says-- your Redeemer, who formed you in the womb: I am the LORD, the Maker of all things, who stretches out the heavens, who spreads out the earth by myself,

Colossians 1:15-20 The Son is the image of the invisible God, the firstborn over all creation. For in him all things were created: things in heaven and on earth, visible and invisible, whether thrones or powers or rulers or authorities; all things have been created through him and for him. He is before all things, and in him all things hold together. And he is the head of the body, the church; he is the beginning and the firstborn from among the dead, so that in everything he might have the supremacy. For God was pleased to have all his fullness dwell in him, and through him to reconcile to himself all things, whether things on earth or things in heaven, by making peace through his blood, shed on the cross.

Acts 5:3-4 Then Peter said, “Ananias, how is it that Satan has so filled your heart that you have lied to the Holy Spirit and have kept for yourself some of the money you received for the land? Didn’t it belong to you before it was sold? And after it was sold, wasn’t the money at your disposal? What made you think of doing such a thing? You have not lied just to human beings but to God.”

It is de fide that the Three Divine Persons are one single, common Principle of the Creation.

The Council of Florence declared in Decretum pro Jacobitis (1441):

Pater et Filius et Spiritus Sanctus non tria principia creaturae, sed unum principium.

[The Father and the Son and the Holy Ghost are not three principles of creatures, but one principle.]

St. Thomas Aquinas, addressing the question "Whether to create is proper to any person?," writes:

To create is, properly speaking, to cause or produce the being of things. And as every agent produces its like, the principle of action can be considered from the effect of the action; for it must be fire that generates fire. And therefore to create belongs to God according to His being, that is, His essence, which is common to the three Persons. Hence to create is not proper to any one Person, but is common to the whole Trinity.

Nevertheless the divine Persons, according to the nature of their procession, have a causality respecting the creation of things. For as was said above (Question [14], Article [8]; Question [19], Article [4]), when treating of the knowledge and will of God, God is the cause of things by His intellect and will, just as the craftsman is cause of the things made by his craft. Now the craftsman works through the word conceived in his mind, and through the love of his will regarding some object. Hence also God the Father made the creature through His Word, which is His Son; and through His Love, which is the Holy Ghost. And so the processions of the Persons are the type of the productions of creatures inasmuch as they include the essential attributes, knowledge and will.

In two editions of the Bible, the notes to Gn 1:26 say 'Let us' implies a discussion between God and his heavenly court.

Perhaps the plural of majesty: the common name of God was Elohim, a plural from. But possibly the plural form implies a discussion between God and his heavenly court. - The Jerusalem Bible - Popular Edition.

And

1:26 The sacred text emphasizes the special significance of this moment: God seems to stop to reflect and plan every detail of his next creation - man. Ancient Jewish interpretation (followed also by some Christian writers) saw the use of the plural "Let us make ..." as meaning that God deliberated with his heavenly court, that is, with the angels (implying that God had created them at the very start, when he "created the heavens and the earth"). But the use of the plural should rather be taken as reflecting the greatness and power of God. A considerable part of Christian tradition has seen the "Let us make" as reflecting the Holy Trinity, for New Testament revelation has made the Christian reader more aware of the unfathomable greatness of the divine mystery. [...] - The Navarre Bible - Pentateuch by Faculty of the University of Navarre.

THE LORD WAS SPEAKING TO THE ANGELS

I'll beg to differ with the previous poster. This is not the Trinity speaking to Himself, as too many mistakenly believe; rather, this is The Lord speaking to the host of heaven, also known as the Divine Council. This is God's assembly, His heavenly family, His entourage, called "bene elohim" (sons of God) in Hebrew. This concept is found throughout ancient rabbinic tradition and is preserved in the Hebrew bible in places like this:

PSALM 82

1God has taken his place in the divine council; in the midst of the gods he holds judgment:

[...]

6I said, “You are gods, sons of the Most High, all of you; 7nevertheless, like men you shall die, and fall like any prince.”a

And, this...

PSALM 89

5Let the heavens praise your wonders, O LORD, your faithfulness in the assembly of the holy ones! 6For who in the skies can be compared to the LORD? Who among the heavenly beings is like the LORD, 7God greatly to be feared in the council of the holy ones, and awesome above all who are around him? 8O LORD God of hosts, who is mighty as you are, O LORD, with your faithfulness all around you?

In the Book of Job, it becomes clear that it was the "sons of God" called "the morning stars" who were with Him in at the creation:

JOB 38

4“Where were you when I laid the foundation of the earth? Tell me, if you have understanding. 5Who determined its measurements—surely you know! Or who stretched the line upon it? 6On what were its bases sunk, or who laid its cornerstone, 7when the morning stars sang together and all the sons of God shouted for joy?

Notice that they were with him when He laid the foundation of the Earth, and they were also with Him when He made Adam. In fact, when He had finished making Man, and had given him dominion over all that He had made, one of the angels had a question:

HEBREWS 2

5For unto the angels hath he not put in subjection the world to come, whereof we speak. 6But one in a certain place testified, saying, What is man, that thou art mindful of him? or the son of man, that thou visitest him? 7Thou madest him a little lower than the angels; thou crownedst him with glory and honour, and didst set him over the works of thy hands: 8Thou hast put all things in subjection under his feet.

So, it should be clear that God was speaking to angels by now, but in case you still have doubts, consider what the Jewish rabbis taught and believed on this verse:

"Let us make man: From here we learn the humility of the Holy One, blessed be He. Since man was created in the likeness of the angels, and they would envy him, he consulted them. And when He judges kings, He consults with His Heavenly household, for so we find regarding Ahab, that Micah said to him, (I Kings 22:19): 'I saw the Lord seated on His throne, and all the host of heaven were standing by Him, on His right and on His left.' Now do 'left' or 'right' apply to Him ?! But rather, [the passage means that] these [angels] were standing on the right to defend, and these [angels] were standing on the left to prosecute. Likewise, (Dan. 4:14): 'By the decree of the destructive angels is the matter, and by the word of the holy ones is the edict.' Here too, He took counsel with His heavenly household. He said to them, 'Among the heavenly beings, there are some in My likeness. If there are none in My likeness among the earthly beings, there will be envy among the creatures of the Creation.'” - [from Tanchuma, Shemoth 18; Gen. Rabbah 8:11, 14:13]

"Let us make man: Even though they [the angels] did not assist Him in His creation, and there is an opportunity for the heretics to rebel (to misconstrue the plural as a basis for their heresies), Scripture did not hesitate to teach proper conduct and the trait of humility, that a great person should consult with and receive permission from a smaller one. Had it been written: 'I shall make man,' we would not have learned that He was speaking to His tribunal, but to Himself. And the refutation to the heretics is written alongside it [i. e., in the following verse:]'And God created (וַיִּבְרָא) ,' and it does not say,'and they created וַיִּבְרְאוּ.'” - [from Gen. Rabbah 8:9]

This rabbinic tradition is fleshed out in the Targum Pseudo-Jonathan version of this story:

"And the Lord said to the angels that ministered before Him, who had been created in the second day of the creation of the world, Let Us make man in Our image, in Our likeness..." - Gen. 1:26 (Targum Pseudo-Jonathan)

You may wonder why English bibles say "God," if this is true. The answer is that for a long time scholars misunderstood the meaning of the word "Elohim." If you study the passage in Hebrew, you'll note that in Genesis One "Elohim" is speaking, but in Genesis 2 "Yahweh" talks with Adam. This has been grounds for criticism by scoffers who claim that scripture is teaching two different creation accounts by two different deities. But, the truth is that the term "Elohim" includes Yahweh, but is not exclusive to Yahweh. Angels are also "Elohim." Today, we would simply say "Spirits."

I hope this helps.

For further study on this subject, I would recommend Dr. Michael Heiser's (resident scholar at LOGOS Bible Software, and Ph.D. in Hebrew and Semitic Languages) recently released book which goes into depth on this topic, and many others like it. It's called "The Unseen Realm."

You can find out more about the book here.

Blessings!

The first thing to keep in mind is that in the Old Testament, doctrine of the Holy Trinity is not at all explicit. The passage in Genesis 1:26 is frequently interpreted as a prefiguration of the Holy Trinity, but it would be a mistake to say that the human author of Genesis is affirming anything about the Divine Persons.

Similarly, it would be a mistake to think that the author had the Holy Spirit in mind when he wrote of the “Spirit of God” (note that the word for “spirit” could also mean “wind”) who “was hovering over the face of the waters” (Gen. 1:2).

In fact, God did not reveal the Holy Trinity to us until He sent Jesus Christ, the Son. It is the “sending”—the “mission”—of the Persons that reveals them to us. (See John 17:18, John 20:21, and 14:16, regarding the Missions of the Persons.)

Naturally, creation is, in fact, the work of all three Persons of the Trinity, and so even though the sacred author knew nothing about the Trinity, the Trinity was at work in the world, from the moment of Creation. God chose to reveal His Triune nature, however, only with Jesus Christ.

Hence, it is possible that the sacred author, under the inspiration of the Holy Spirit, gave the Old Testament a foretaste of the revelation to come by portraying God as refering to Himself as “we.” The “Spirit of God” may indeed be a hint regarding the Holy Spirit. However, from the Old Testament alone, we cannot draw any definitive conclusions about the Holy Trinity—for that we need the revelation given to us by Jesus in the New Testament.

More à propos to the O.P., there is no way to tell for sure if the one “speaking” when God speaks is the Father, or who exactly He is referring to when He says “we.” Certainly, the sacred author did not have the Trinity in mind, but the passage can legitimtely be interpreted in that vein, in the light of the New Testament.