You have to turn on Allow Symbol Property Connections. Once you to that you will see options for choosing which field it will look to. See the below image. Important. The field for the color needs to be a Hex code color OR the web safe color name. you can Google Search for "Web Safe Color Name". or "X11 Color Chart".
One of the nice things about using the Hex Codes is if you add number 01 through 00 it will adjust the opacity of the color. More hand on polygons than points. You can even make a domain out of the ColorNames to have a hand drop down menu.
I'm attempting to size my points by total production (double) and color by operator (text). So if I understand you correctly, I need to create a new field and populate it with a hex color code for each unique operator?
Also, when I use this method, the size differences between my points are hard to discern. Most of the points look small and no matter what I set the size to, they remain the same size. Am I missing something on how to control the size of the points?
I can successfully control point size when I'm just using graduated symbols, but I think I am doing something wrong with this Symbol Property Connection.