To modify this icon color you must modify the custom-theme.css file, learn how to modify any file in this article: http://help.ordering.co/ordering-builder-my-ordering-co/cms/edit--pages
Now in the file, you need to modify this segment of the code:
And write the hexadecimal color of your choice.
Glad we can help,
Have a nice day.
Regards, Pol Zepeda