If I understood the question correctly, I would make a volume corresponding to all the parts + 1mm all around, a shell to make it empty, this volume put in transparent white + 2 extrusions to symbolize the straps. All accompanied by a commentary.
I don't know inventor, but on SolidWorks, it's easier to draw it in "hard" than to do schematics (especially since the "package" remains simple). Otherwise, on SW, you can play with the display style.