Computer science gives you a much broader range of options, and probably positions you better to get a follow-on credential in cyber security.
Cyber security as a stand-alone, without a solid computer science foundation, sounds to me like it would lead to more IT/technician type roles.
EDIT: also, for what it's worth, with cybersecurity ramping up as a discipline on the military/government end of things, I suspect that the "best" jobs in that field will all involve a TS/SCI that the former military guys will have out of the box.