As far as you faced such problem while using Color Swatches Pro module, perhaps, there is no 'Add to Cart' button in your Magento theme. As a consequence, there are no swatches on category page.
To solve the problem, open
Admin panel/System/Configuration/Amasty Extensions/Color Swatches Pro/Advanced settings
and perform the actions that are shown on the picture:
Are you looking for the same functionality for your Magento 2? Look at our Color Swatches Pro solution.