How do I take a photo like this on a canon eos m?

It has something to do with the shutter staying open for a long time or something.

"It has something to do with the shutter staying open for a long time or something."

Yes, you need to take a long exposure, from the image, it looks like the photographer took a series of images (20 to 30 seconds each) and then using a program like Photoshop CC, merge them together.

You need

* a tripod
* a remote shutter release
* and use the manual focus mode on your camera/lens.

The link below is a sample such photo merger when I was attempting to capture a meteor shower. As you can see, I only captured one meteor. I used the time lapse feature on my old Nikon D300 to take around 60 exposures of 30 seconds each. Bulb? See if it comes up after 30 seconds in the shutter speed setting. Learn your craft.

Bulb? See if it comes up after 30 seconds in the shutter speed setting.

Learn your craft.