Party Data Model / Universal Data Model Example
I think you need to step back first and familiarise yourself with the notation, which seems to be Barker:

http://www.agiledata.org/essays/dataModeling101.html

The Party Role structure does illustrate a hierarchy of a type, but each of the subtypes uses the same primary key, the Party Role ID.
Presumably, when implemented each of these entities would have varying attributes, so wouldn't be implemented as a single PartyRole table.  Also, there will be business rules of what other tables the party roles could relate to.
But in terms of Party Relationships, what you have seems correct