custom solenoid trigger circuit
For the first circuit remove the top mosfet and connect the diode and solenoid to the 60V supply. Make sure the MOSFET you use is fully saturated by the output voltage of the arduino, otherwise you'll find they die. You may also want to add more snubbing circuitry.

In the second circuit you've read the schematic wrongly, the component isn't a opto isolator, but an opto-isolated solid state relay.