Is it to cover the whole machine? If it's just for the playfield a few of us on here made them out of yoga mats - https://www.pinballinfo.com/community/threads/the-today-i-received-thread.14471/page-181#post-453051
We made 6 or 7 covers a few years ago. i don’t use them since I built the new pin room, so will happily sell - if i can remember where we put them. Will have a look over weekend and post pics.