Your eyes don't have quantum energy packet receptors :-) A normal photograph is made by bouncing light off something and detecting it. If you are using a CCD, you are still using false colour. It just happens to correspond to the true colour.
In this experiment, the electrons interact with the photons to produce quantum energy packets, which the microscope detects. What is the colour of the quantum energy packets? The question has no meaning, because they aren't light. Since the colour is arbitrary, they can choose to colour it in any way they find useful.
Having said that, I also don't understand the "photograph".
