The visitors took the lead in the third minute when Davy Propper collected the ball on the edge of the box and unleashed a strike that beat Hidde Jurjus to find the net.
However, the home side got a goal back just before the break when Andrew Driver won the ball in midfield from Guardado and drove forward to fire his strike into the bottom corner.
In the second half, De Graafschap pulled within a goal as Alexander Bannink finished off a well-worked move with a neat finish from close range.
PSV regained their advantage when the hosts failed to clear their lines from a cross into the box before De Jong seized possession and drilled his effort pas Jurjus.
Zoet kept his side ahead with two impressive saves to deny Kabasele and Vincent Vermeij. The stops allowed Luciano Narsingh to put the game beyond the reach of the home side in the 83rd minute, while Gaston Pereiro capped the victory with a sixth goal in stoppage time.
The result moves Cocu's men up to third place, while De Graafschap remain bottom of the table.