You can extend the cable by splicing some 18/2 or 20/2 AWG cable onto the end of the transformer’s cable. Use B-wire connectors or wire nuts to complete the splice.
The same solution to crimping using b-wire connectors as described here:
Having an electrician put in an outlet would be fine if there were no outlet at all near the Hardwire 16-F location, but if all you need to do is extend the cable a little bit there is no reason for that kind of expensive solution.
You can add an optional cam lock, but in most cases a screw is used in the screw lock on the right hand side to hold it shut.