No hint of a 'hot' or 'cold' indicator.
For any newcomers, this is the latest entrant in 43Showers, a chronicle of all of the hotel shower handles I meet. They're all different, and most are confusing when you're staring at them early in the morning for the first time.
Look for the "43showers" tag to see the rest of them. There's a site for all this, but it's not worth looking at yet.