From the manual for this inverter, it is only rated at IP20 ie prevents fingers from being inserted but has no protection against swarf or water. You need to mount it away from swarf and coolant, which I find gets everywhere, possibly also fitting a shield to further improve the level of protection.
Some inverters have a removable front panel which you can mount next to the machine but this one doesn't. However, you can wire up a remote box that has start / stop / direction / job / speed etc controls. This might only need 2 toggle switches and a pot, depending what you want to control. The control signal are safe and low voltage, so nothing special is required for safety.
I wouldn't mount the controls above and behind the machine, as you would need to lean across the rotating machinery to turn it on / off etc – really not recommended! You should also think about wiring up one or more large red e-stops or incorporating a kick switch.
If you have a cabinet, you could even mount the main inverter inside it, assuming there is some reasonable degree of ventilation.
Murray