On the left navigation options, click the one for Covid 19 County Level Data, then click through to the Data and Tools page.
On the left nav here, scroll and click to Covid 19 in the State under Data Dashboards.
Click Orange on the list of counties on the left (currently third on the list) This will give you a historical graph of number of positive cases going back to March. You can see how much the OC cases have jumped in recent weeks.
ETA - for comparison. Click on Los Angeles, first on the list, to see how others graphs are different. The LA graph has gone steadily up over the time while the OC graph was relatively consistently low until maybe a month ago, then increased significantly.