Label the graph as a "figure" at the start of the graph's caption. For example, Fig. 6. The population in China continues to rise.
Reference the graph in the paragraph when you write about its contents. For example, "Despite attempts to curb China's booming population, the birth rate soars (see fig. 6)."
Cite the graph in your bibliography and footnotes by including the author's name, graph's title [figure]. Follow with: The book's author, The book's title (in italics). City, State: Publisher. For example, Smith, G.K. (2004). System Development Life Cycle [Figure]. In T.R. Peltier, Information Security Policies and Procedures. Boca Raton, FL: Auerbach.