There are WordPress job board plugins which can add job board functionality to your site for less of an investment than you may have thought.
“If your site is focused on a particular niche, adding a job board is a great way to encourage visitors to check back regularly and even sign up to your newsletter for job updates.”
WordPress Job Board Plugins List
The article from WPMUDEV also contains a list of themes, but our preferred approach is a custom design and then we build it using Bootstrap or Foundation.
Source: http://premium.wpmudev.org/blog/job-board-themes-plugins/