The embeddable can be customised by heading to 'Widget Settings' under 'Deliver' in the main menu.

From this screen you can change the colour of the embeddable, where it appears and how it appears.

For example, you may want the embeddable to appear along the left hand wall of your site in red and say “Click here for help”, alternatively you may want a blue button with a question mark to appear in the bottom corner of your page which opens the embeddable. It’s up to you.

If you'd like to tweak the look of your articles, see adding custom CSS to your articles