framed nodelabel in a graph

If there were a way to access the handles to the node label text objects, it would be easy to draw rectangels (or circles) around the labels. But I am not aware of such a method.

An alternative is to remove the node labels and add them back in as text objects. Then we would have the handles to the text objects and their coordinates, extent, etc. The demo below demonstrates how to do this. Note that this comes at a cost. The text objects acting as node labels are no longer associated with the nodes. So, if there's a change in the graph that causes a rearrangement of the nodes, the text objects will not follow.

% Create graph and plot it
A = triu(magic(4));
names = {'alpha' 'beta' 'gamma' 'delta'};
G = graph(A,names,'upper','omitselfloops');
h = plot(G);
% Store a copy of node labels, then remove the labels 
NodeLabels = h.NodeLabel; 
h.NodeLabel = repmat({''},size(h.NodeLabel)); 
% Add text objects for the labels. 
% * You may have to adjust the HorizontalAlignment & VerticalAlignment to suit your needs
buffer = range(xlim())*0.02; 
text(h.XData + buffer, h.YData, NodeLabels, 'HorizontalAlignment', 'Left', ...
    'VerticalAlignment', 'Middle', 'EdgeColor', 'k', 'FontSize', h.NodeFontSize, ...
    'Color', 'k', 'FontName', h.NodeFontName);