The General Instruction of the Roman Missal (GIRM) assumes that the priest and deacon are facing Liturgical East, towards the Lord. The following are the paragraphs from the GIRM instructing the priest or deacon to turn towards the people.
Once the Entrance chant is concluded, the priest and faithful, all standing, make the Sign of the Cross…Then, facing the people and extending his hands, the priest greets the people”
Upon returning to the middle of the altar, the priest, facing the people and extending and then joining his hands, invites the people to pray, saying, Orate, fratres (Pray, brethren).
Then the priest, with hands extended, says aloud the prayer, Domine Iesu Christe, qui dixisti (Lord Jesus Christ, you said). After this prayer is concluded, extending and then joining his hands, he gives the greeting of peace while facing the people and saying, Pax Domini sit simper vobiscum (The peace of the Lord be with you always).
When the prayer is concluded, the priest genuflects, takes the host consecrated in the same Mass, and, holding it slightly raised above the paten or above the chalice, while facing the people, says, Ecce Agnus Dei (This is the Lamb of God).
Then, standing at the chair or at the altar and facing the people, the priest, with hands joined says, Oremus (Let us pray);
If a prayer over the people or a solemn formula for the blessing is used, the deacon says, Inclinate vos ad benedictionem (Bow your heads and pray for God’s blessing). After the priest’s blessing, the deacon, with hands joined and facing the people, dismisses them, saying, Ite, missa est (The Mass is ended, go in peace).