Which Chart to Use

My first thought is to use something like a Gantt chart. The bar position and length can tell you time of day, the category axis will be day of the week, and each supervisor is a different bar color (data series). Number of audits could be shown in the data label for each bar.

I doubt the built in Gantt chart type will be able to handle this much information, so I expect you will need to build the Gantt chart in the "old fashioned" way -- as a stacked (and clustered) bar chart.
Clustered and stacked bar chart tutorial (note that it is really a regular stacked bar chart with the data appropriately arranged in the spreadsheet): https://peltiertech.com/clustered-st...mn-bar-charts/
Simple Gantt chart tutorial (so you need to combine this technique with the clustered and stacked technique): https://www.excel-easy.com/examples/gantt-chart.html

Does that sound like a workable solution?