diff --git a/src/sage/graphs/generic_graph.py b/src/sage/graphs/generic_graph.py
index bb804bcfd1b..acbf386833f 100644
--- a/src/sage/graphs/generic_graph.py
+++ b/src/sage/graphs/generic_graph.py
@@ -763,20 +763,40 @@ def __mul__(self, n):
 
             sage: G = graphs.CycleGraph(3)
             sage: H = G * 3; H
-            Cycle graph disjoint_union Cycle graph disjoint_union Cycle graph: Graph on 9 vertices
+            Disjoint union of 3 copies of Cycle graph: Graph on 9 vertices
             sage: H.vertices(sort=True)
             [0, 1, 2, 3, 4, 5, 6, 7, 8]
             sage: H = G * 1; H
             Cycle graph: Graph on 3 vertices
+
+        TESTS::
+
+            sage: Graph(1) * -1
+            Traceback (most recent call last):
+            ...
+            TypeError: multiplication of a graph and a nonpositive integer is not defined
+            sage: Graph(1) * 2.5
+            Traceback (most recent call last):
+            ...
+            TypeError: multiplication of a graph and something other than an integer is not defined
         """
         if isinstance(n, (int, Integer)):
             if n < 1:
                 raise TypeError('multiplication of a graph and a nonpositive integer is not defined')
             if n == 1:
                 return copy(self)
-            return sum([self] * (n - 1), self)
-        else:
-            raise TypeError('multiplication of a graph and something other than an integer is not defined')
+            ns = self.order()
+            ntot = n * ns
+            vint = {u: i for i, u in enumerate(self)}
+            edges = ((i, j, l) for u, v, l in self.edge_iterator()
+                     for i, j in zip(range(vint[u], ntot, ns),
+                                     range(vint[v], ntot, ns)))
+            return self.__class__([range(ntot), edges], format='vertices_and_edges',
+                                  loops=self.allows_loops(),
+                                  multiedges=self.allows_multiple_edges(),
+                                  immutable=self.is_immutable(),
+                                  name=f"Disjoint union of {n} copies of {str(self)}")
+        raise TypeError('multiplication of a graph and something other than an integer is not defined')
 
     def __ne__(self, other):
         """
@@ -809,7 +829,7 @@ def __rmul__(self, n):
 
             sage: G = graphs.CycleGraph(3)
             sage: H = int(3) * G; H
-            Cycle graph disjoint_union Cycle graph disjoint_union Cycle graph: Graph on 9 vertices
+            Disjoint union of 3 copies of Cycle graph: Graph on 9 vertices
             sage: H.vertices(sort=True)
             [0, 1, 2, 3, 4, 5, 6, 7, 8]
         """