It doesn’t.

If you’re taking a pure “infrared” image it will look like night vision goggles. Since infrared doesn’t have a color that we can see, it just ends up as brightness value data going into the camera’s sensor. It’s just black and white since the sensor only has a brightness value to reproduce.

For this image I used a filter that allows the infrared through, making things like foliage brighter and giving it sort of an orange hue, while kicking out other wavelengths. I then use basic color adjustments to make the orange-ish foliage that the camera produces look super bright red. You can alter it to pretty much any color you like. All infrared pictures are ultimately false color, so it’s up to you what you want it to look like.