Preheat oven to 350°F (175°C).

In a medium bowl, combine graham cracker crumbs, melted butter, and sugar. Mix until crumbs are evenly coated.

Press the crumb mixture firmly into the bottom and up the sides of a 9-inch pie pan to form the crust.

Bake crust for 8-10 minutes, then remove and let cool completely.

In a large mixing bowl, beat cream cheese until smooth and creamy.

In a separate bowl, whip heavy cream to stiff peaks.

Gradually add powdered sugar, vanilla extract, and sweetened condensed milk to the cream cheese, mixing until combined.

Gently fold whipped cream into the cream cheese mixture until smooth and fluffy.

Divide filling evenly into separate bowls (one for each gel color you plan to use). Add a few drops of different gel food coloring to each bowl and mix gently until you achieve desired pastel shades.

Spoon dollops of each colored filling into the cooled crust, layering and swirling with a butter knife or skewer to create a marbled effect.

Chill pie in the refrigerator for at least 4 hours or overnight until set.