Thank you for your question. Currently you can register predefined styles only but not presets. You can find an example here. This example describes how to add new color for Button element. Here is a result http://prntscr.com/evzt2b It was added a long time ago when there was not visual style editor. You can add custom styles for other elements following this example.
Also we have added your request to our features list. Thank you for your idea.