Hey! This is late, but my 3 1/2 son just recently started a new daycare, so I understand... unfortunately:)
Each morning in the drive, I ask if he'd like to be carried or walk holding hands into the center. I ask him when we're in the room where he'd like to sit with me for 3 minutes, and he sits in my lap and we hug and talk about what the other kids are doing, and then I give a hug and kiss and wave goodbye through the window. I think it's comforting to him to know I too miss him daily.
When I get home, each day during dinner, I ask about the kids in his class by name (How was Ethan? Did you play blocks with Max?), ask what he ate for lunch and snack, and what he liked best about his day. This shows him I'm interested in his day and its details.
He shares his special day with me, and I do the same with him. He feels special because I love and miss him during our time apart, and I want all the details not just the "overview":)
Good luck!:)