Preheat the oven to 350 degrees and prepare a 9x13 inch baking pan with a light coating of cooking spray. Set aside.
In a large bowl, combine cake mix, water, vegetable oil and eggs. Mix until thoroughly combined.
Pour batter into the prepared baking pan and bake for 25 minutes or until a toothpick inserted in the center comes out clean.
Allow the cake to cool, then using the handle of a wooden spoon poke holes over each inch of the cake. Set aside.
In three small bowls, combine each jello package with 1 cup boiling water. Whisk together until fully combined.
Use a Tablespoon to pour jello mixture into the holes in cake, alternating colors according topreference until each hole has been filled. Do not use all the jello.
Place the cake into the refrigerator and let it cool for 2 hours. If desired, color the whipped topping and spread over the cooled cake and top with sprinkles as desired before serving.