Thank god -- a new thread. About something practical.
Why not ask your colleague to lunch and find out whether s/he is feeling overburdened, targeted, etc.? Then you can get a better feel for what it's like to be on the other side of this particular fence, and, if appropriate, offer to share some of those duties, as necessary.
This is an excellent idea. My guess is that your colleague, being new and self-conscious about being a good citizen, probably has no idea that it might be completely ok to say "no" to some of this stuff. But if s/he had the option of saying, "Why don't you ask my colleague JH, who I know is interested in contributing to diversity blah blah blah....." that would take off some of the pressure. It's really not appropriate for your colleague to be asked to do so much service work at this early stage in her/his career, especially if there are high expectations about publishing for tenure. This kind of overburdening of women of color, in particular, is very common on campuses that don't have a lot diverse faculty, and administrators across campus may have no idea that they're all tapping the same person.