Alan Irvine was sacked as manager on Tuesday, so Preston had caretaker Rob Kelly in charge.
Darren Carter had a shot parried by Colchester goalkeeper Ben Williams after eight minutes.
Simon Hackney had a cross saved by Preston goalkeeper Andy Lonergan after 11 minutes.
Chris Brown opened the scoring with a header from inside the six-yard box at the near post from a left-foot Ross Wallace right-wing inswinging corner in the 13th minute.
Paul Ifil had a long-range shot saved after 18 minutes.
In the 27th minute Chris Sedgwick on the right made it 2-0 with a deflected angled shot over the keeper that bounced into the centre of the net from a Brown assist.
Joel Thomas replaced the injured John White for the U's after 34 minutes.
Eddie Nolan's cross was saved after 37 minutes and Jon Parkin's low straight shot was saved after 39 minutes. Richard Chaplow had a cross saved after 42 minutes.
Just before half-time Hackney fouled Sedgwick and the left-foot right-wing Wallace free-kick was saved.
Parkin made it three in the 48th minute with a close-range shot under the keeper from Brown's flick on.
It was 4-0 in the 50th minute when Parkin lobbed the keeper from the edge of the area.
Brown's curled right-foot shot from the edge of the area hit the post after 51 minutes but bounced off keeper Williams into the back of the net to make it 5-0.
Kemal Izzet replaced Hackney after 54 minutes.
Darren Carter made it 6-0 after 63 minutes with a shot into the bottom right corner.
Veliche Shumulikoski replaced Chaplow in the 68th minute.
Magnus Okuonghae fouled Parkin, who scored his third, 7-0 from the spot in the 72nd minute sending the keeper the wrong way.
Stephen Elliott replaced man of the match Parkin after 72 minutes and Neil Mellor came on for Brown a minute later. Thomas was booked for a foul on Wallace after 88 minutes.