There are several different ways to display date information and how you'd like it displayed on each generation of your chart is up to you. Here are the different options and how to switch between them.
1) To start, click the "Advanced" tab in the left sidebar, and then the "Generation" tab to open the Generation sidebar panel.
2) Then choose for which generation you would like to modify how dates are displayed, either by clicking on the generation in your chart of by selecting it from the drop-down menu.
3) Then click the "Information Displayed" drop-down menu and choose how you would like your date to be formatted.
Examples of each option are given below.
You may need to modify the generation radius (a.k.a. how "long" each cell is as measured from the center), as well as the font size to make long names fit. You may also find Text Offset useful if you find that it looks like the name is in the wrong place in the cell.
Here's a little video showing this feature in action--this video was made using the old editor, but all of the functionality is the same--you just access the generations panel differently!