Whenever you have color options in the visualization editor, you can use the color picker. A square color icon next to the field marks the color picker.  

Choose Colors

  1. Click the colored square in the field that you are working on
  2. Click a color on the color wheel or the color tabs
  3. Change the color's saturation using the left slider bar
  4. Change the color's brightness using the right slider bar
  5.  Click on OK to close the Color Picker

Choose Harmonious Colors

  1. Click the colored square in the field that you are working on
  2. Select a base color
  3. Click Schemes
  4. Select a color from the scheme options 
  5. Click Ok