You're right, the universe as a whole isn't too visually interesting. But perhaps God has different definitions of "art" and "beauty" than humans - especially as He probably doesn't depend on sense organs like "eyes" and "hands" the way we do. Maybe He finds beauty in the elegance of mathematics, or the intricacy of subatomic particles and their interactions.
Also, I'm quite pleased to have found this thread, in particular because I've always thought charts of isotopes of the elements - like this one - look just like a stroke from some celestial paintbrush:
"The universe is a lot more complicated than you might think, even if you start from a position of thinking that it's pretty damn complicated to begin with." - Douglas Adams