How to change Stars in Webform-star module?
The webform-fivestar module currently doesn't have the option to select which star widget to use, however there is a patch you can apply at https://www.drupal.org/project/webform_fivestar/issues/2071161

There is information regarding how to apply patches at https://www.drupal.org/patch/apply

You can then select the widget per component, when editing the component, in the display settings (see screenshot).