Diwali is about card parties and you need to dress up like a queen and not a joker.
This looks is simple and elegant for pooja time in the evening.
A satin saree will look perfect for the occasion of diwali.
If you want to go a little extra and be a show stopped then you can go with a heavy lehenga like this one.
If you are invited for a diwali prty then showup looking like a firecracker.
you can go for something like this that is Indo western for bhai Dooj.