Gallery Property: TemplateFill
The DAX:
If(ThisItem.'U_STU_AcademicStats.DIPLOMA_EARNED'= "Yes" && ThisItem.'Graduation Location' <> "-", Color.LightGreen, ThisItem.'U_STU_AcademicStats.DIPLOMA_EARNED' = "No", Color.LightCoral)
Add an Icon to you Gallery.
Icon Property: Icon
If(ThisItem.CeremonySignIn, Icon.Check, Icon.ThumbsDown)