R Graphics Cookbook, 2nd edition by Winston Chang.
From the webpage:
Welcome to the R Graphics Cookbook, a practical guide that provides more than 150 recipes to help you generate high-quality graphs quickly, without having to comb through all the details of R’s graphing systems. Each recipe tackles a specific problem with a solution you can apply to your own project, and includes a discussion of how and why the recipe works.
Read online here for free, or buy a physical copy on Amazon.
Do us all a favor, buy a hard copy of it. It encourages healthy behavior on the part of publishers and it’s easier on your eyes.
Enjoy!