Spray a 9-by-13-inch cake pan with nonstick baking spray.
Bake the cake according to the cake mix package instructions in the greased cake pan. Let cool. Poke holes in the surface of the cake with a toothpick or thin skewer.
Pour the sweetened condensed milk, evaporated milk, whole milk and vanilla into a pitcher and whisk thoroughly. Slowly pour the milk mixture over the top of the cake. Let the cake sit and absorb the milk mixture until it has soaked in, 20 to 30 minutes.
Spread the whipped topping evenly over the top. Decorate with the sprinkles and cherries.