Either have jMeter generate the graphs or export the data to excel. It really depends on what your Jmeter tests /do/; typically I have a script that I run that slowly increses the number of users on a cadence. So look for the delay to suddenly skyrocket - that's your inflection point.

It's possible, especially on one machine, that you reached network saturation or a delay in your own CPU, so check the server logs for how long things took on the server when you hit that inflection point (time where delay suddenly explodes) - then begin a conversation with management about what that might mean and if it is "good enough."

Good luck!