Pop the popcorn kernels using the coconut oil according to your preferred method (stovetop or air popper). Set aside in a large bowl.
In a saucepan, combine powdered sugar, corn syrup, and butter. Cook over medium heat, stirring constantly, until the butter is melted and the mixture is smooth.
Remove from heat and stir in vanilla extract and salt.
Divide the popcorn into separate bowls for each color of food coloring. Pour a portion of the sugar mixture into each bowl and add a drop or two of a different neon food coloring. Toss gently to coat the popcorn evenly.
Spread the colored popcorn in a single layer on parchment-lined baking sheets to cool and harden.
Once cool, gently mix the colors together in a large serving bowl or serve in individual portions.