I just found one approach from John and tried it (posted on How do I change the color of platform headings/titles? - JMP User Community).
It works for only with some color (e.g. Medium Light BlueCyan) but it does not work with some color (e.g. white)
Also, when I saved Script to data table, this color setting is not saved with the script. When I run the saved script, text color turn back to black. I need to manually add this code in the saved script so that the color is reproducible. but if I change color of X,Y axis. It works with all colors. and JMP can generate script for X, Y axis color for me in saved script.
Dispatch( {}, "Graph Builder", FrameBox( 1 ), {Text Color( "Medium Light BlueCyan" )} ),
I am using JMP Pro 17.