The Claris/FileMaker relationship graph is a unique aspect of its environment. It's where you create connections which satisfy not only the logical and structural connections between your data, but it's also where you create connections purely for the aesthetics of your user interface and the functional operation of your solution. So, it's very important that you employ as many organizational tools as possible.
Why field name?
The connecting lines (relationships) between Table Occurrences are shown based on the current View by: setting within Manage Database > Fields area. Try this, switch the View by setting to field type and then return to the Relationships tab to witness a reordering of all your well placed occurrences.
Table occurrence placement: needs to be added.
Table occurrence colors: needs to be added.
Use emoji characters within Relationship Graph notes in order to convey more information and meaning about your graph.