You have two options:

1. Either lower your browser's zoom level (I had to reduce it to 90% because I had *Hide left navigation* disabled in [profile *Settings*](https://askubuntu.com/users/preferences)).

1. Or enable *Hide left navigation* in your [profile *Settings*](https://askubuntu.com/users/preferences/) so you can see the graph at 100% zoom.

It seems the behavior has changed a bit since the issue was first mentioned in [The reputation graph disappears when zooming in past 100%](https://meta.stackoverflow.com/questions/415576/the-reputation-graph-disappears-when-zooming-in-past-100).