WARNING: This page is about a different car, the 2004 Volvo S40, 2003 Volvo S40, 2002 Volvo S40, 2001 Volvo S40, and 2000 Volvo S40. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: ABS Sensor
Courtesy of VOLVO CARS OF NORTH AMERICA.
Clean thoroughly around the sensor.
Remove the ABS cable from the bracket.
Remove the screw. Carefully remove the sensor from the wheel spindle with a twisting movement.