You know those canopies you get outside shops. The type that looks like a pram hood.
I made one of those for a sawbench and it was pretty effective.Using it from multiple lengths of coathanger wire bent to shape, then stuck to heavy duty polythene and joined the ends just by bending them slightly and using whipping twine.
It was that canopy shape so when you cranked over the saw to 45deg it would still be effective.
I took it off, and never got around to replacing it when i changed to a bigger saw so havent any pics. But the concept of it should be something you should be able to visualize.
Fixes onto the saw body and also the underside of the table, and filled any gaps with stuck on foam blocks.
If oyu think about the underside of he saw, where the blade is exposed, just fitting a bit of cardboard doesnt work because when you raise or lower theres no give so it would crumple. I thought about that problem so designed my hood to be similar to a concertina effect so it could move, expand and contract and still enclose the blade area and thus cut down on the expanse the extraction has to try to deal with.