One option would be to draw the knife edge and the edge at the transition from the bevel to the flat. Use Fredo’s Curviloft to fill in the hollow grind surface. It seems to me I did a sort of tutorial on this sort of thing. I’ll see if I can find it.
This might help.
The knife in the example didn’t have a hollow grind but you would just replace the straight edges at the ends of the grind with shallow curves if you really need to show the bevel as hollow.
As a side note, you need to be using SketchUp Pro.
