Create a Voronoi image with random RGB colors

1. Create a Voronoi Noise node [?].
2. Create a Gradient Map node.
3. Connect [Voronoi Noise > image] to [image > Gradient Map] [?].
4. Add multiple colors to the Gradient at different positions.

To add more randomness to the final Voronoi image:

1. Create an Random Noise node.
2. Create a Bezier Curves node.
3. Create a Bezier curve above the random noise image. You can set the random noise image as a Reference image with the top menu command View > Set Reference image.
4. Create a Curve Sample Image node.
5. Connect [Random Noise > image] to [image > Curve Sample Image].
6. Connect [Bezier Curves > curve] to [curve > Curve Sample Image].