Diagrams of the Energy Centers, as well as a detailed description of these centers, can be found in Dr. Joe’s Book Becoming Supernatural, Chapter 4.
For a quick visual of the placement of these centers, view the cover of the Blessing of the Energy Centers ll meditation.
You can also see a video visual by viewing the Introduction to the Progressive Workshop YouTube Video.
In addition, in the Blessing of the Energy Centers 1 Meditation, there is an excellent description of the Energy Centers. The links to the book and video are below: