In this paper, we consider various graphs, namely: power graph, cyclic graph,
enhanced power graph and commuting graph, on a finite semigroup $S$. For an
arbitrary pair of these four graphs, we classify finite semigroups such that
the graphs in this pair are equal. In this connection, for each of the graph we
also give a necessary and sufficient condition on $S$ such that it is complete.
The work of this paper generalize the corresponding results obtained for
groups