Please explain how

[Richard L]

There are two processes involved here.

Temperature change of the liquid (specific heat) does not affect the greater effect of cooling by evaporation much (latent heat).

Water:
- Specific heat capacity of water ........ 4.2kJ/kg/C
- Latent heat capacity of water ......... 2260KJ/kg

You can see from above the two effects.

There is another advantage of having a warmer liquid with lower viscosity, it atomises better at the nozzle tip. There is no advantage of cooling the liquid in the tank.