A sewing or crafts supply store will have reflective material. You can sew it on. They even have lace and plenty of other types of materials. How nice it looks will then depend on your cutting and sewing skill. A design like the you have there wouldn't be hard, maybe if you don't have a friend that sews a tailor or dry cleaner that offers tailoring services might do it for a small fee if you cut out the pattern and just give it to them. Wouldn't be waterproof of course. That's the lowtech way