To manage the default settings for your categories, go to Theme Options -> Category Template.
Category display settings
The same as for single posts and pages, you have the options to change the display settings for each category separately, if for any reason you need different layouts for different categories. In your admin panel, go to Posts -> Categories to access the separate options per each category.
Category colors & featured images
One of the additional features is the ability to choose a different color and a featured image for each category. By default, all categories will display the same color inherited from content accent color, but if you want to change it, there is a simple option provided for each category on its edit screen:
Take a look on the process of customizing category options in this short video: