Hi,
In my eyes the datasheet is clear.
1) +U (positive supply)
2) -U (negative supply)
3) M (Measurement output)
4) 0V (GND, reference)
A symbol (connection diagram, schematic) has no reference to mechanical construction. The order of signals does not follow the order of the connector.
And this is godd the way it is. Schematics follow other rules: positive supplies UP, GND and negatuve supplies DOWN, signal (information) flow from left to right. A schematic is to see how the circuit works, what is conected to what, it should be easy to follow the signals.
In best case there additionally are the pin numbers shown next to the signal names.
Example: One physical IC may contain 4 Opamps. On a schematic you may have 4 independent standarized Opamp symbols plus one power supply symbol. All symbols may even be placed on different sheets of the schematic.
Nowadays I often see (mainly for hobbyists projects) schematics using black boxes with numbering in order of the pins of the according IC (package).
I always find it way harder to comprehend the circuit function. This is not how it should be. Hobbyists get it tought the wrong way ... and have hard time to (re) learn to draw schematics the right way when the projects become more complex or more professional.
Klaus