The Advanced Permissions module adds several new tabs to the Role edit page. In Advanced: Categories, you can select the categories that will be available to users with this role:
With these restrictions, the user will see only allowed categories:
In Advanced: Products, it's possible to give access to all products, only specified products, own created products, and products created by the users sharing this role:
Refer to the below examples for Selected Products:
The user sees only products selected by the admin:
Please note that in case of restricting access both to categories and products, the user will only see the products that match both the permission settings in Advanced: Products and the available categories.