Hi,
It's possible in several ways.
First, if you set the "ordering column" setting to "ordering", as it is the case by default, the products will be sorted based on the value under the "order" column you can see when you look at the backend products listing.
So you could simply use that to manually define the order of each product in each category thanks to the input fields in that column (with the save icon next to the "order" title at the top of the column):
i.imgur.com/p6RmY34.png
Second, you could create one menu item for each category as child menu items of your main shop menu item in order to have a similar tree of menu items as you have for the categories. That way, in each menu item, under the "products options" tab, you'll have that same "ordering column" setting, allowing you to override the main setting of the HikaShop configuration for the listing of that particular menu item and thus for the corresponding category only.