here is a script that may help. It was done in Poser 7. 

It works on only the current material.

It will collapse all inputs and previews so each node is just a little box.

It also arranges them in columns and rows. 5 nodes per column  unless theres lots of nodes  and then it puts them in 5 columns and what rows are needed.

Note: this is not intelligent but a brute force arrangement. It should however bring every node into view for you to rearrange as needed. 

It doesnt change the mat pose so you would have to run it every time , or save the result as a material or collection.