Show code snippets in the tree option is available in the view menu. It toggles whether matches will be shown this way (option is on):
or this way (option is off):
Link with editor option can be toggled from the view toolbar. When the option is on, an editor is opened when you single-click a match, navigate with your keyboard and navigate using Previous Match / Next Match buttons. When the option if off, an editor is only opened when you double-click a match and when using Previous Match / Next Match buttons.
The editor allows customization of the colors used for highlighting identical and differing pieces of a match.
Choose Window > Preferences, navigate to General > Appearance > Colors and fonts. SimilarCode settings are under the corresponding category.