I am looking for a graph that shows the shrinking of the volume of a standard compost pile over time, i.e. how the volume gets less for each day.
Where can I get a chart for that?

In what way are you talking about volume? Water volume, or over all weight loss or mass shrinkage? I don't know of a chart without going to the University.

Well, the volume, not the water content, not the weight. E.g. I start with 1000 litres and after one week there is 750 l , after another week there are 650 l, etc.