Sequence of commands for the above:
> /usr/bin/safaridriver -p <port>
> curl -X POST --data '{"capabilities":{}}' -v http://localhost:<port>/session
Creating a new session outputs a sessionId, which we can then use to execute the url command with:
curl -X POST --data '{"url": "https://www.libertymutual.com"}' http://localhost:<port>/session/<sessionId>/url