Bring in already drawn pages, either showing the separation of light and darkness, and let the kids color the pages with colored pencils, crayons or paint. The sun and moon could be on two sides of one page or each could have its own page. Supply materials for the kids to color with, and set a time limit for the activity. The kids can either bring home their work to hang on the fridge or put up their artwork on the Sunday school wall or bulletin board.
Give each kid a pencil or marker and have them draw their interpretation of the first day of creation. Or pull out the smocks and let the kids paint the way they see God bringing light into the universe. They don't have to try to capture the entire event; they could draw or paint symbols of light. They can write a bible passage under the event or have a title at the top, which reads: "First Day of Creation."
Have the kids put on a little skit to reenact the first day of creation. Take squares of cardboard, have them color one side black, the other side yellow. Have the kids line up or huddle together, holding the black side of the square outward. One kid could read the passage from the bible when God said, "Let there be light." Have each kid flip his square to the yellow side. Get creative, ask for ideas from the kid to help illustrate the event.
If the kids can write, have them tell the story in their own words. Or gather them together and have them collaborate to tell a tale. They could write it from the point of view of the sun, or possibly tell a story about how Night had a new friend, Day. The story could also be from Night's experience, telling how Day let him see for the first time, possibly showing him how big the universe really was.
Turn off all the lights. Select a kid to play the role of creator, and have him stand by the light switch. When it's dark, have all the kids pose in different positions, placing themselves around the room. Make sure to tell them to be careful and remove all potential objects. Either the adult or the kids can say, "Let there be light!" That cues the "creator" to flip the switch and see what everyone is doing.