One example, actually given in Hitchens' book, would be the daughter of Nathan Landow. On page 18, Hitchens wrote:
"... of course, Mr Landow's daughterwoks at the White House, causing nobody to ask how she got her job. In Clinton's Washington there is always affirmative action for such people"
Landow was Maryland Democratic Party Chairman, and a major fundraiser for the Democrats. Further, according to the article Good old reliable Nathan in the Weekly Standard:
He has been business partners with Vernon Jordan
I suspect that he is also referring to Monica Lewinsky.
In an article titled 'It's not the Sin; It's the Cynicism', published in Vanity Fair in December 1998, Hitchens wrote:
"... Ms. Monica Lewinsky, who--we forget at our peril--got her "job" at the White House only because her mother’s chum had kicked in the better part of half a million to the D.N.C. (There is, in Clinton’s Washington, always affirmative action for such cupcakes.) ..."
- article text quoted in full Ontology site of the Philosophy Department, State University of New York at Buffalo
Given the similarities in both the choice of words and the context, it seems likely that is was also Ms Lewinsky that Hitchens was referring to in the book.
However, it is worth noting that Vernon Jordan claimed that he had only done two things for Monica Lewinsky:
I did two things for Ms. Monica Lewinsky.
I assisted her in trying to find employment in the private sector in New York City. I referred her for interviews at American Express and at Revlon, where I am privileged to serve as a director. I also referred her to Young & Rubicam, a New York advertising agency.
Secondly, when she was served with the subpoena and -- at her request, I recommended a very competent Washington lawyer, Mr. Frank Carter. I actually took her to Mr. Carter's office, I introduced them, and I returned to my office.
As far as I am aware, he hasn't stated explicitly that he helped Ms Lewinsky get her job as an intern at the White House.