In addition to the global reputation line graph that you can get on your stackexchange.com profile, there is also a per-site graph accessible from your profile page.
Instead of being on the landing page, there is now a "graph" option. Selecting it will provide a bar graph readout, divided into the same pagination as your reputation page normally displays. You can hover over a bar to look at the exact reputation for that day, and clicking it will provide a readout for that individual day.
In the end, this provides a very different utility than the global reputation line graph, but that just means you have more tools to analyze your trends in reputation growth. ♪
Below is a sample, including the readout for clicking an individual day.