From a visual perspective, this can be done with a gantt chart. Create a calculation End-Start, call it whatever you want, but "Duration" seems fitting. Change your mark type to Gantt and drop Duration on Size.
Other dimension pills you drop on the view will draw more gantt bars.
From a calculation perspective of "on this day, how many jobs were active" - that's a ton more complicated. If the gantt option satisfies, I'm stopping there. If the gantt option does not get you what you want, we can talk more about the calculation, but it'll get complicated in a hurry.