Add this to the top of the file inside the first curly brackets
Step 5 - Add images
Images can be added to any node easily in the following way
First, we have to remove the shape with shape=none. Then we add the path to
the image and set a background colour to match the background of the added
image and the rest of the graph. labelloc = b sets the label to the bottom.
Step 6 - Colour the links
We can add colour to show what speed the links between the nodes run at very
Step 7 - Add a title
Finally we add a title with label="Network Diagram";
The final image
The final image looks like this. It shows the hierarchy of the switches and
even where the servers are connected as well.