There is a block of toilets to the right of the bus station building, as you face it.
It is a 2 minute walk to the taxi rank. (150 metres)
Exit the bus station onto Calle Zoilo Ruiz-Mateos (the street you face with the bus station building directly behind you).
Turn left towards the roundabout.
At the roundabout, slightly to your left, is a pedestrian crossing.
Cross the street, and turn left.
Cross the small road, Calle Carlos Cano.
You will now be at the taxi rank.