How do I add a legend to a selected graph?

I want to add a legend in graph G according to different selected edges. Can this be done with just one graph G

?

Here is an example of toys to play with. I have a plot G

.

adj =[0 0 1 1 1;   % adjacency matrix
      1 0 1 0 1;
      0 1 0 1 1;
      1 1 1 0 1;
      0 0 1 0 0]
G = digraph(adj);

      

        
        
        
      

    

I selected all the edges with three colors according to the edge types. The 3 edge types indicate that in my case there are 3 different relationships between nodes.

This is how I selected all the edges:

M(:,:,1)=[0 0 1 0 0;1 0 0 0 1;0 0 0 0 0;1 0 0 0 0;0 0 1 0 0];
M(:,:,2)=[0 0 0 1 0; 0 0 1 0 0;0 1 0 0 1;0 0 0 0 0;0 0 0 0 0];              
M(:,:,3)=[0 0 0 0 1; 0 0 0 0 0; 0 0 0 1 0;0 1 1 0 1;0 0 0 0 0];

      

        
        
        
      

    

The difficulty in my problem is that I need to remove vertices that have degree less than any integer (say 2). So I cannot plot 3 graphs independently.

rmvNode=find(outdegree(G)<2);    % outdegree is the reason why single G is neccesary
adj(rmvNode,:)=[]; adj(:,rmvNode)=[];
M(:,rmvNode,:)=[]; M(rmvNode,:,:)=[];
G=digraph(adj);

      

        
        
        
      

    

Then we can build it.

for k=1:3           %Looping depending on the third dimension
    [r,c]= find(M(:,:,k));  %Finding non-zero elements
    s{k}=r;     t{k}=c;    
end
h=plot(G);
highlight(h,s{1},t{1},'EdgeColor','r');
highlight(h,s{2},t{2},'EdgeColor','g');
highlight(h,s{3},t{3},'EdgeColor','b');

      

        
        
        
      

    

My ideal situation would be a legend like this: label the red edges as "type 1", assign the blue edges to "type 2" and assign the green edges to "type 3". I want something like this:

Once again: I cannot plot 3 plots independently according to 3 pages in M, merge 3 plots together, and then add a legend. Since, as you can see, outdegree

requires the input of a whole graph G

, it is impractical to divide G

by G1

, G2

and G3

.