That's an interesting question. In the world of C++ which is peppered with people preaching best practices and codes of conduct, I've never really seen an article or heard someone talk about file organisation. That's not to say no one ever has, I've just never met them
Personally I think it's down to preference, although the type of project does influence how I lay out my source directory. For instance
both of my
libraries have a relatively oragnised structure with files placed in directories based on what they do, eg graphics or audio. The header files are arranged like this too (much in the same way as SFML's) because it makes it much easier to include them in another project.
On the other hand, for projects which use those libraries I tend to dump all the files in a
single src folder, or possibly split them into
src/include. This is mostly down to laziness as I tend to assume that, unlike libraries, I'll be the only person that ever really uses them
