It's possible that it is position/angle agnostic; depends on how it's sensor is designed to work, and that I haven't found any references for.
Some use sensors embedded in the actual crankshaft (TSDZ2; weakens the shaft though); some use them in a "ring" on the crankshaft by the bearing, some in the casing, etc; some are strain gauges, some are magnetically-controlled hall sensors (moving the magnet slightly by deformation of the crankshaft/etc changes the reading), and so on. Plenty of room for variation and so it could work without being in any specific position.
Some sensors (erider) have different versions with the wire coming out in different places for different BB shell / frame designs. If this one is like that, it might still have specific placement requirements but not knowing which version you wouldn't know which way it was meant to point. :/
My guess is that if the install guide (if it's from the manufacturer, or a dealer/etc that has successfully used them) shows a particular way of doing it (only one install or several installs shown but with only one install orientation), that's the "best" way to get the results it needs. If there's no particular way shown (meaning, they show several installs, each of which has a different orientation) then it probably doesn't matter.