I'm not sure what you mean by "mural art style", can you give an example?

I will say that there was a large-scale mural project that was born out of FDR's New Deal during the Depression. The Works Progress Administration and the Treasury Section of Painting and Architecture were tasked with hiring artists to send throughout the US to paint public murals pertinent to whatever community they were working in. A lot of these murals still exist in post offices around the country, and there's a significant amount of scholarship surrounding them so you shouldn't have much trouble researching them in depth. The link above has a nearly complete list of WPA/New Deal murals in the country so it's a good place to start. You may even have one of these murals in your community or within driving distance!