1. Preheat oven to 350°F (175°C). Grease and flour six 8-inch round cake pans.
2. In a large bowl, sift together the flour, baking soda, baking powder, and salt.
3. In another bowl, beat the sugar and butter until light and fluffy. Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.
4. Gradually add the dry ingredients to the wet ingredients, alternating with buttermilk, mixing until just combined.
5. Divide the batter into six bowls, adding a different gel food coloring to each. Mix until vibrant.
6. Pour each colored batter into the prepared pans.
7. Bake for 15-20 minutes, or until a toothpick inserted comes out clean. Cool in pans for 10 minutes, then transfer to a wire rack.

For the Cream Cheese Frosting:

1. Beat the cream cheese and butter until smooth. Gradually add powdered sugar and vanilla, beating until fluffy.

Assembly:

1. Place the red cake layer on a serving plate. Spread a layer of frosting over the top.
2. Repeat with the remaining layers, spreading frosting between each.
3. Frost the top and sides with remaining frosting.
4. Decorate with rainbow sprinkles and edible glitter.