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.