Control RGB LEDS (common cathode) with a Mosfet or a transistor

will this work?

As drawn no.

the switch simulate the arduino

Not on that simulation it dosn't. You will need to have a change over switch in order to simulate the Arduino.

Also their is no pull up resistor on the gate, meaning that in the time between boot up and the code running the Arduino output will float and cause random LED firings.