Prepare the white cake mix as directed on the box and bake in a 9x13-inch pan. Let it cool completely.
Using the handle of a wooden spoon, poke holes all over the cake.
Divide the pudding mix into two bowls. Add red food coloring to one and green to the other. Stir in 1 cup milk to each until thickened.
Spoon the colored pudding alternately into the holes of the cake.
Spread Cool Whip evenly over the top.
Decorate with festive sprinkles. Chill for at least 2 hours before serving.