That's right. For OS X and BSD's ls, the flag is -G.
Many people customize the behavior of ls by replacing it with an alias that adds extra options. I have the following in my .bashrc, for example:
alias ls='LSCOLORS=gxfxcxdxbxexexabagacad /bin/ls -bFHGLOPW'Besides enabling colors in general, this sets the LSCOLORS variable in order to change which ones ls uses.
Thanks!