You can add a visual link to either your library’s Pinterest account or to one of your boards using the Pinterest Widget Builder. You just enter the URL for your profile or a board, and get back a line of HTML to add to your page.
Examples of the profile and board widgets are below. This is sort of a dynamic screenshot, so if you add new pins, they will appear on the widget. Clicking on these takes you to your library’s board or boards — unfortunately, you can’t click on a specific pin. These examples are using the defaults, but if you choose Advanced Settings, you can specify the size for your widget.
(The Pinterest Widget Builder is found under the information on Pinterest’s Business Accounts, although it’s not clear whether it’s meant to be limited to business accounts.)