The attached diagram communicates the basics of a layered technical system.
The idea is to demonstrate the separation of concerns between pieces and how they fit together.
There is color coding to group certain commonalities together and a legend.
Also, there are icons associated with some pieces too. The icons are not set in stone, from Fontawesome, but might be a good starting point.
See these logos which are included in the diagram:
Would like for you to homogenize the design as it was drawn rather crudely; it can look much better.
Use Omnigraffle or Sketch and provide the original source file as I might make minor edits later myself.
I have a well-defined color palette from which to choose from - not incorporated in this first draft but I will provide later.
The design motif will be minimal. I would like to do is much as we can with grays before overloading it with color.