Lower the 'vertical' sensitivity.
Perry, what is the resistance of the inductor ?
What generates the transient is not the inductor but the switching device, either a mechanical contact or a semiconductor.
How to use the right diode and how to chose them
I guess the inductor is a factor though, because the transient behaviour involves the inductor, as well as the behaviour of the input (such as the input voltage versus time), and maybe some resistance etc in the cable.