This could use more work getting the double-edges properly aligned (fisheye alert), but other than, this is about the best I could do with the source image (link below).
Note: just because the accidental color variation looked nice, I smoothed out the reddish-purple tones along the bottom & bottom-left edges, leaving them intact. The original art almost certainly would have featured only a single purple hue for the entire outer edge.
Thank you John Kirby:
https://www.ipdb.org/showpic.pl?id=1&picno=6603&zoom=1