Okay, Robert’s comment made me go hunting around. So, these are terrible quality, but they will give you an idea:
The mostly-white cover, which is the one I have:
The interior cover art from that same edition, which is indeed very nice:
And another edition, which is also pretty good:
All of these are superior imo to the extraordinarily boring green cover:
The centaurs and blimps and things are quite accurate. The nymph-like girl, perhaps a tad less so.
You found the interior cover art — that is so totally cool! I remember that it blew me away when I saw it so long ago. And the story proved every bit as amazing as the art.
The green cover just evokes some sort of generic SF story; it doesn’t really mean anything. With the original artwork, you knew that wonders lay within.
Thanks to Google’s image search, I was able to find a larger version of the interior cover art here.
Thanks, Robert!