'蟹风筝’意思是指形状或造型象螃蟹一样的风筝。类似的还有「鸟风筝」「鱼风筝」等等。

1. a crab-shaped kite; or

2. a crab pattern on the kite.

I would assume that it's a "pale ink-colored crab-looking kite". "墨" is the black ink used in Chinese calligraphy and paintings. "蟹风筝" means a kite that is drawn and/or shaped like a crab. The part that stumbles me for a bit is the "淡墨色", that's new to me. I didn't know it could be described that way.

If I'm not incorrect, you're talking about a "crab-shaped" kite