I just watched the new blu-ray of this movie, shot in 65mm Todd-AO by Leon Shamroy. Shamroy has always interested me because of his use of colored lighting, which was sort of a signature style of his, particularly in the days of 3-strip Technicolor. Most of "Cleopatra" is lit with a minimal use of colored lighting other than for the backgrounds -- often using blue gel for moonlighting, but keeping that blue very pale and subtle on close-ups. You can see an example of the more typical night interior lighting here:
But there are two scenes at night in the tomb of Cleopatra near the end of the movie that have always stood out for me in terms of the expressive use of color, in particular the use of cyan lighting on gold walls. The first one is between Cleopatra and Mark Antony, the second has Octavius confronting Cleopatra in the same room.
You can see the effect in these frames:
Generally he keeps Elizabeth Taylor in a near white key light:
But at one point she steps forward into some blue moonlighting used on Richard Burton:
Burton's lighting is more dramatic, with the mixed colors visible -- cyan on the pillars, blue on other parts of the room, slightly gold light coming from fire: