Ah, I'm afraid that's totally hardcoded - I should probably extract the color to settings at some point.
The color it's set to is (40, 152, 176, 155), so you might be able to have a fainter version of the noise show up in your desired color by inverting graphics/fx/noise.png so that it becomes the color you want when the hardcoded color is applied to it. I'm not sure if there's enough play there or if the red channel being set to 40 will make it too faint to be visible.