Visualize voxel-wise P-value maps with different colors for each voxel depending on its value


I want to visualize a brain statistical maps (containing only hippocampus regions) in a glass brain template. I can create this by creating mesh files, vtk, and overlay them. However, the vtk file does not contain color information I think, so the hippocampus regions were treated as a mask with same color (like the visualization in this paper:

I wonder how to assign different colors based on different p-values?

Thank you for your help