LF node graph for scripting theory

[HESA]

Hello im starting a big complex project.

And before starting coding i would like to make a node graph plan.
So i will only have to follow my plan.
That way i will not forgot what i made and how it was working
and how its suposse to work for the next class wich is not made yet.

Im looking for something
where i can create one big node
exemple SceneObjects Class
And in this node there will be input/output

Exemple
Output is QMap<int index, ObjectClass>

And it connect to node for ObjectClass

And this node have input or output for :
public Vector3 Pos
public QString Name
etc...

Well if you know a good software for it let me know, i already googled alots and tryed Xmind wich is close to what i want but not allowing me to create in/output for my node.

Anyway Thank you !!!