Move the legend 

@@ -39,6 +39,9 @@
     axis_space         => 6,
     bar_spacing        => 1,
     bargroup_spacing   => 20,
+    legend_placement     => 'RC',
+    legend_marker_width  => 12,
+    legend_marker_height => 12
 ) or die $graph->error;
 
 $graph->set_legend(@products);