An elliptical one. The Wikipedia page you link gives a signfiicantly different apogee and perigee and a period of 20.8 hours. So, on average, it moves West to East a bit faster than the Earth does, but at apogee it's moving more slowly and the Earth overtakes it a bit (which are the "S-bends" in the track). It swings a little North of the equatorial plane while approaching the Earth, and a bit South while receding. At the moment of the above screenshot it is close to perigee.
Each full cycle of the wave pattern is an orbit, so after roughly six orbits (120 hours) when the Earth has turned five times beneath it, it will get back to the same longitude. This fits with the apparent size of the wave pattern on the map, which is credibly about 4 time zones.