(Design) Resistor on anode or cathode?
With 1 LED and 1 current limiting resistor it does not matter and there is no convention.  Not for schematics (where there are a lot of conventions for readability).  And not for PCB layout where practicality, space and good engineering normally win out.

That said, in some cases the resistor needs to go between the power supply and LED (such as common cathode displays):


And in others between the LED and ground (such as common anode displays):


But these are examples where the design (arrangement of LEDs) dictates the placement.