Prepare the Jelly: In a saucepan, mix 4 cups of water, white sugar, and jelly powder. Stir constantly over medium heat until the jelly powder dissolves completely and the mixture starts to boil.
Color the Jelly: Remove the saucepan from the heat and divide the jelly mixture into three separate bowls. Add a few drops of red food coloring to one bowl, yellow to another, and green to the third. Stir until each bowl is evenly colored.
Set the Jelly: Pour the colored jelly into flat trays or shallow containers and let it cool to room temperature. Once cooled, refrigerate for about an hour, or until the jelly is completely set.
Cut the Jelly: After the jelly has set, cut it into small cubes and set them aside.
Prepare the Creamy Base: In a large mixing bowl, combine fruit cocktail (drained), the jelly cubes, heavy cream, condensed milk, and evaporated milk. Stir gently until well combined.
Chill and Serve: Transfer the mixture to a serving dish, cover it, and refrigerate for at least 2 hours to let the flavors meld. Serve chilled for the best texture and flavor.