There was no uniformity in dark empire or dark empire 2 with the lightsaber colors so the orange could have been on purpose i don't have the source book only the comics.

But in Dark empire 2 they all have blue white blades.

I just assumed that was Sedriss on the cover of the source book and that as a fan of Vader his saber was the same color but in the comic when he uses one at all its blue.

Who painted or drew that cover for the source book?

Could it simply have been an artists choice or a colorists decision on the color?

I am no longer sold on it absolutely being red though after seeing the comics again and finding that the darksiders use non red sabers.