Preheat oven to 350°F (175°C). Combine white cake mix, water, oil, and eggs in a large mixing bowl and mix until smooth, about 2 minutes.

Divide batter into four bowls and add food coloring to each bowl to create colored layers.

Grease a 9x13 inch baking dish and alternate spoonfuls of each colored batter into the dish.

Bake according to package instructions, typically 25 to 30 minutes. Allow to cool for 10 minutes.

Poke holes in the cooled cake using a wooden spoon handle in a grid pattern.

Whisk together instant pudding mix and milk, then pour over the cake, filling the holes.

Cover and refrigerate for at least 2 hours.

Whip heavy cream with powdered sugar until soft peaks form, then spread over the cake.