I found this code here http://lists.common-lisp.net/pipermail/slime-devel/2012-March/018497.html.
Original author is Max Mikhanosha.
Add this to your .emacs
(slime-setup '(slime-fancy slime-repl-ansi-color))
run slime and test it:
(format t "~c[31mabc~c[0mqweqwe~%" #\ESC #\ESC)
or
(sb-ext:run-program "/bin/ls" '("-l" "--color=yes" "..") :output *standard-output*)