If you choose to publish your automation, you get a Marketing Page. This article is about styling the 'long description' of that page:
View this Marketing Page (bonus: see the markdown we're using by duplicate this template and checking out the Marketing Page of the associated Workbase).
Custom HTML + CSS: You can write HTML and CSS directly in the long description for your Marketing Page. This FAQ can't fully explain how to use HTML or CSS, but in a nutshell you want to write HTML elements and add "inline" CSS.
Add icons: You can add Font Awesome icons (v4.7.0). This requires you to write custom code referencing the unique classname of each icon. From Font Awesome, click on an icon to view it's classname:
... then use that classname in an HTML i element, like this: <i class="fa fa-gavel"></i>