There are two options of the product display, the same model group as on product page or each color of the same model as individual page depending on how you wish to communicate your product to the buyers.
Product grouped by model
The same model can be assigned for different colors of one product. This groups the colors on the product page. You may find all the colors listed together on the product page Shirt.
Product separated by colors
The display of having each color as the individual product page allows the buyers to view all the colors when entering the category page without worrying the buyers may miss some colors of the same model.