7-12V Power supply + USB
You will see that the Servos have 3 wires [GND, Power, and Data/Signal]. You can connect your external power supply to GND and Power of the servos, and connect the GND and Signal wires from the Servos to the Arduino.

By connecting the Grounds of the Arduino and Servos together, they share the same 0V reference and you will not damage either by powering the Servos from a higher voltage and the Arduino from USB.

It is not necessary to connect the Arduino Vin or barrel jack to the external power supply. Look at the Servos+power supply as one independent unit, and the Arduino+USB/Computer as a separate independent unit, and the only things connected between them should be GND and the servo signal/data wire.