When you have a shape, line, or multiple shapes and lines selected you can change their properties at the same time.
To do so, make your selection and in the Home tab click on Fill or Line Style to see the options available.
For example, let's say you selected your entire organizational chart:
You can change the fill color of the selected shapes and it will apply it to all shapes, leaving the lines alone:
Learn more about styling shapes.
Similarly, if you choose to modify lines, it will affect the lines connecting the shapes and the border of shapes.
Learn more about styling lines.
You can change several properties of your selected items this way including:
Changing the Font and Other Text Properties