Solution
A 
Value Mapping or 
Color Scheme Override will not appear on a Grafana panel (such as a table) unless the panel's 
Cell Type has been configured properly.
To configure the 
Cell Type to allow for background or text color changes, follow the steps below:
- Select the All tab from the panel options.
 
- Scroll through the list of options to find Cell Options >> Cell Type.
 - Set Cell Type to Colored Text or Colored Background, depending on your preference.
 
- The Value Mapping or Override should now apply. If not, click Apply to save your changes.
 - [OPTIONAL] If your panel applies other colors that you did not define in a Value Mapping or Override, it is also necessary to change the Color Scheme option:
	
- Continue scrolling through the list of options until you find Standard Options >> Color Scheme.
 - Change the value to Single Color.
 - To the right of the drop-down menu, select the circle icon to select a color. Select the Transparent option.
 - Click Apply to save changes.