There are two ways you can use wpml with WooSwatches. Here we are assuming that you already have products setup with WPML and it is working with default dropdowns. First check what product translation interface you are using. Visit settings tab under WPML/WooCommerce Multilingual menu.
Method 1 (for WPML Translation Editor) :- Visit attributes tab under WPML/WooCommerce Multilingual menu. add translations to all the attributes and its options.
Once translation done , click on below given button "Synchronize attributes and update product variations"