Write like this:
Dear Sir,
This is to bring to your kind attention that, (As per the plan, i am traveling to ____ to visit a college to meet placement officer to hire candidates for the vacancies in our company / due to some strategic meetings in the office, i could not catch bus to reach my home ). So i hereby requesting you to advise our travel desk to provide a cab for me.
Thanks & Regards,
send like this...!