Here's the quote:
My commutation ticket came back to me with a dark stain from his hand. That any one should care in this heat whose flushed lips he kissed, whose head made damp the pajama pocket over his heart! (Fitzgerald p. 155).
The context is that Nick is on the train (on the hottest day of the year) heading to have luncheon with Daisy, Jordan, Gatsby, and Tom. The paragraph before this is the conductor exclaiming that it is hot.
From what I can tell the narrator is saying that he doesn't care about the conductor's sexual life, but I can't see how that is remotely related given the context. Anyone know what this quote is supposed to mean?