In 1-quart saucepan over medium heat, heat milk and cereal about 5 minutes to steep (make sure milk does not boil).
Meanwhile, add a few drops food coloring to whipped topping; stir slightly, leaving colorful streaks.
Drain cereal from milk; discard cereal, saving flavored milk. Pour coffee into mugs; add some of the flavored milk to taste. Top each with whipped topping and additional cereal.