\version "2.18.2"

colorPitch =
#(define-music-function (parser location p col) (ly:pitch? color?)
   #{
     \override NoteHead.color =
     #(lambda (grob)
        (let ((pitch (ly:event-property (ly:grob-property grob 'cause) 'pitch)))
          (if (equal? pitch p)
              col)))
   #})

upper = \relative c' {
  c4 d es f
}

\score {
  \new Staff  \upper
  \layout { }
}

\score {
  \new Staff {
    \colorPitch #(ly:make-pitch 0 1 0) #green
    \upper
  }
  \layout { }
}

\score {
  \new Staff {
    \colorPitch #(ly:make-pitch 0 2 -1/2) #blue
    \upper
  }
  \layout { }
}