this is probably a font issue on your end, i dont have color emoji working because i need a different blend of carefully chosen linux packages and configs to get that working but i have the default mono glyphs which have patterns instead, making it at least somewhat readable.

(i think chrome doesnt support colored emoji yet? i know they work for me on firefox)
get an emoji font and it should either start rendering the colors properly for you, or at least it will use the correct fallbacks.
noto emoji (ands its
color version) seems popular as an emoji font, you can try that.
alternatively, we could get flash to add twemoji to the chat, which will change all emoji displayed into images.