The tooth profile on an elliptical gear changes around the gear. It is the same involute profile as used on a circular gear with the same radius of curvature at that point. An elliptical gear will then roll smoothly along a rack, or mesh with another elliptical gear at 90° phase. The important thing is to make sure that the circumference of the pitch ellipse will be an exact integer multiple of the tooth pitch.
You can draw the tooth profile using the involute curve, or you can roll the gear numerically along a trapezoidal rack.
Tooth profiles are usually generated by the cutting process. They do not have to be accurately drawn.
We need more specific information before answering further.