Legend for color code used in fence diagram

Im trying to add a variable legend entity to fence diagram to show color code used in selected logs in particular fence daigram. I was trying to change the field with data to library color table but there is no color graphics to choose in symbol type drop down menu and result is no legend at all. Is there any way to show used colors in fence diagram? Im using colour table in symbol design to fill specific field in GEOL table to describe stratigraphy of layers.

Thanks for any advice