Color options for printing to PDF?

When I select colors for the black background of the LibreCAD drawing screen, I pick light colors like Cyan and Yellow that are visible.

I can print all colors as black, but I want to be able to share drawings by printing to PDF and include colors to highlight various aspects of the drawing.  If I de-select the B/W option on print preview, the colors are included in the PDF.  Unfortunately they are not visible on the white background of the PDF.

Is there any setting or configuration file that would let me "map" screen colors to different print colors?

There is no mapping option. You can change the screen background color to white or grey. I use light grey, that's not too much a strain on the eyes.