Preheat the oven to 350 degrees. Spray a 9x13 baking dish with nonstick baking spray and set aside.
Add all of the wet ingredients for the pumpkin cake to a bowl and mix to fully combine. Add the dry ingredients and mix until they are just incorporated, careful not to overmix.
Pour the batter into the prepared baking dish.
Allow the cake to bake for 25-30 minutes or until a toothpick comes out clean. Let cool completely.
Whisk together the three coconut milks for the tres leches.
Cut the cooled cake in half. Place the bottom half of the cake back into the baking dish.
Use a skewer or fork to poke holes all over the cake.
Pour half of the milk mixture over the top of the cake.
Stack the top of the cake over the bottom. Repeat the process of poking holes all over the cake.
Pour the remaining coconut milk mixture over the cake.
Allow the cake to chill in the refrigerator for at least 6 hours before serving.
Top the chilled cake with Dairy Free whipped cream and a sprinkle of cinnamon.