This typically occurs when the color space worked with in the host differs from the colorspace used by Looks.
Looks works within a studio RGB (sRGB) color profile. If your host isn't working within an sRGB color profile, you can adjust it to better match itself between Looks and the preview.
- In After Effects, the color profile settings are found under File > Project Settings > Color
- In Final Cut Pro X, the color profile matches whatever that is of your monitor, which is adjusted under Apple > System Preferences > Display > Color