my $color = "lightgrey";

while (<DATA>)
# chomp and split

next if (impact = 0);

$plot->add_node($idname, label => $idname"); # parent node

if ($impact in range(1..10){
  $plot->add_edge($idname => $fooname, color => "darkblue");
         }
elsif ($impact in range(11..30){
  $plot->add_edge($idname => $fooname, color => "blue");
         }
elsif ($impact in range(31..50){
  $plot->add_edge($idname => $fooname, color => "cyan");
  } # etc ... 
else {
  $plot->add_edge($idname => $fooname, color => "red");
  }

} # we close the while loop
# and create the plot...