Preheat the oven to 350 degrees F.
Grease a 13x9 cake pan. Set aside.
In a large bowl, whisk together the cake mix with the eggs, oil, and milk until just combined.
Pour the cake batter into the prepared pan.
Bake in the oven for 28-30 minutes, or until a cake tester inserted into the middle of the cake comes out clean.
Allow to cool about 20 minutes, or until just slightly warm.
Combine the coconut milk and sweetened condensed milk in a medium bowl and whisk until well blended.
Use the handle of a wooden spoon to poke holes evenly across the cake.
Pour the coconut milk mixture over the cake, making sure it gets down into the holes.
Refrigerate the cake for about 2 hours to allow the cake to set up.
Spread the thawed cool whip evenly over the top of the cake in a thick layer.
Sprinkle the top with the shredded coconut.
Garnish with maraschino cherries if desired.