The ABI on GOES-16 is not exactly like a camera. Instead it collects light across different spectral bands and stores them independently. So when you see a color image from GOES, it's actually a composite of specific bands. I don't know how NESDIS (source of the imagery here) does it, but a common way to produce "true color" imagery for this class of satellites is to superimpose their red band, their blue band, and an interpolated "green" band.

The ABI also collects shortwave infrared light, which is still possible to observe at night. Since the satellite's normal use is for atmospheric weather observations, it's common to show the SWIR bands at night so that that clouds are still visible.