What "data of the nodes" do you want to retrieve? Do you want the coordinates of the plotted points?
B = graph(bucky);
h = plot(B);
X = h.XData;
Y = h.YData;
fprintf("Node 1 is located at (%f, %f)\n", X(1), Y(1))
% Turn on the axes ticks so you can check the coordinates
ax = ancestor(h, 'axes');
ax.XTickMode = 'auto';
ax.YTickMode = 'auto';
xticks(-5:5)
% Draw lines -- X marks the spot
xline(X(1), 'r')
yline(Y(1), 'r')
