Here's how I store mine for the winter -
I roll it up on the roller, then turn it half a rotation per day for about 1-2 weeks - this makes sure all water will eventually roll out of it.
Then I just leave it "as is" on the posts where the roller is mounted with a long piece of plastic bungeed around it as a final protective layer.
It's made from plastic and the winter will not hurt it, year 3 of doing this on a 3 yr cover that's on it's 4th year - still looks almost new.