Anyone know how to sort this mess?

I try to build a project management process diagram with Omnigraffle, took almost 6 hours to finish it, after I finish I found out it very difficult to read, so I am thinking is there any solution that can make this diagram organized fast and easy to read?
Don’t bother with knowledge and terminology in project management, just try sort this thing out, make it easy to read and understand.
I need every box have inputs and outputs from different directions in the diagram.
(For example, inputs only point into the box from left and outputs only come out from right side of box) 😄

Anyone know how to sort this mess?

Perhaps experiment with switching to OmniPlan ?

It sounds like you just need to add magnets to your graphics on the left and right only to get what you need. Select the graphics and choose Left and Right magnets in the Properties Inspector.