Whether you like it or not, you will probably end up in the industrial city of León, 56km west of Guanajuato, thanks to its importance as a main bus hub within the state of Guanajuato. Also, it's only 20km from Aeropuerto Internacional del Bajío.
It's unlikely you'll need to stay here; bus connections are plentiful. If you want to fill an hour or two before a bus connection, it's worth wandering the streets surrounding the bus terminal, known as the Zona Piel, Leather District. (León has a long history of supplying goods: in the 16th century it was the center of Mexico's ranching district, providing meat for the mining towns and processing hides.)