Do you have a picture of it?? What may be a cocoon to some could be a butterfly to others.LOL Just kidding,but a picture would help.
Kathi

I hope this link works. I have seen it on ebay. Just do a search for cocoon jacket if this doesn't work.

Here is a link that might be useful: cocoon jacket

That's very pretty,and i'm sure you can probably find a comparable pattern in any of the pattern books.
Kathi