Thanks for reaching out.
It's a great idea to add color swatches to your theme as this can provide the customer with more content to encourage a purchase. By default, Shopify will allow you add variant options and allow the customer to swap between the options created. Using the Impulse theme, we can navigate to the Theme Editor and find the theme settings which is located under the sections of the online store. I took a screenshot from my test store to show you the section I am referring to:
Once you select on the theme settings we can then navigate to the Products to find the settings to enable color swatches.
I did come across to finding the developers guide on how you can turn on color swatches using the Impulse theme, feel free to check it out.
Let me know if you have any questions.