Using Siemens PCS7 as a guide, (your colors may vary).
A closed valve is Medium Dark Gray in color and the valve icon is perpendicular to the flow. When commanded to open, the valve changes position to parallel with the flow and flashes green/white while opening. Once open, it becomes solid green. When commanded closed, it moves to perpendicular again and flashes gray/white while closing. Once closed,it is steady gray.
If faulted it stays perpendicular, turns red, with a Lightning bolt through the middle.
If interlocked, it stays in the "safe" state, usually closed, and a small padlock symbol is shown.