I sewed this up just before leaving for ICFA, so didn’t get a chance to post it beforehand. One of the benefits of sewing my own swimsuit from my own fabric is that it’s super-easy to sew a matching cover-up. I printed a yard of Spoonflower chiffon, cut off the white selvedge edges, hemmed it. Easy-peasy.
I could have stopped there, and just had a wrap, but no, I had to be a little extra — I took some of that selvedge waste fabric and made two ribbons out of it (make a casing, turn it inside out, iron flat), and attached those to the two ‘top’ corners of the rectangle (assuming you’re holding it with a long edge on the top).
(You could, of course, just use actual ribbon. I hate waste, though, so it was satisfying using up some of the selvedge edges.)
Then I tied them together in a bow, and you could re-tie it every time, I suppose, but my vision was that I could just drop this over my head and one arm easily when I got out of the pool, and yup, it works great. I was going for a hint of a sari drape shape to it, and I think that worked really well.
The end result is nice enough that I can walk through the hotel afterwards, and people ask me wait, what is that cool thing you’re wearing? Is that a dress? Nope, just a swim cover-up! I mean, I wouldn’t go in a damp swimsuit and cover-up to attend a conference panel, but this is perfectly nice for lounging poolside and chatting with colleagues, without feeling too under-dressed.
Pleased. 
