This is often an uncomfortable or awkward subject in many Western Cultures, not so in the culture of most Muslims! It is commonplace to talk about faith in everyday conversation.
Find your commonalities. You both believe in one God, prayer, Creator and creation, giving offerings, charity. You are both people of Holy Writings/Books etc. You will both learn a lot from each other by talking about these things.
As interested as you are in wanting to share what is on your heart, start by being a learner. Ask questions. Ask which prayers, practices, holy writings are most meaningful to your friend. Share meaningful verses, practices in your life and the life of your family.
Familiarize yourself with the Koran, particularly the third chapter which has much to say about Jesus (Isa). This can lead to more discussions about the things you do agree about — Jesus being born of a virgin; Jesus healing the sick and raising the dead; Jesus currently being in heaven with God. In the third Sura or chapter it mentions Jesus as the word of God.
Another name used for Jesus in Islamic tradition is Ruh Allah, which literally means Spirit of God.
We are all spiritual beings as well as physical beings. Don’t shy away from talking about spiritual things. But above all, let love and genuine concern and compassion guide the direction of your friendship.
—Lady of Prayer