The chameleon effect cannot be turned off without reverting the source changes that enabled it.
Atm the means to alter the color used does not work, seen here in bug report though in one of the dupes a dev marked it as a wishlist which is curious https://bugs.launchpad.net/unity/+bug/975350
Additionally, even when working you are not able to use #000000 which would allow for a non-colored launcher, bug report here - https://bugs.launchpad.net/unity/+bug/924586
If the former bug is fixed you can achieve a near colorless launcher by setting a single color (r,b, or g) to a value of 1, adjusting the opacity to suit & using "Edge Illumination .." for launcher icons
If both bugs are fixed then you can use #000000 with some opacity to remove the colored effect
Update - both bugs now have a proposed fix up for review. Have tested here & now a custom color can be set including #000000 which depending on opacity set can negate the 'colored' effect