I found it in this Ladybug advertisement from 1968:
I have had this fabric, below for a while (thrift store find, of course). Wouldn't it be perfect made into a suit like that one? Not for ME - just in general?
Well, I think it would. Here are some patterns from the same era to choose from. Not the very same exact suit style, but similar, at least. Shorten the skirt a little, if you want.
We have McCall's 9566:
Or perhaps McCall's 7621:
Let me know what you decide. My vintage fashion imagination wants to know.