The rider whose father and grandfather hail from Coventry, shot in the last stage of the race to beat a top class field to the finish line in a time hour three hours 41 mins and 11 seconds.
Cooke won the rainbow jersey beating World Champion Holland's Marian Vos and the 2004 winner Judith Ardnt.
She told Cycling News after the race: "I am very, very happy. "I am very happy following Beijing. When we started I was relaxed because I had met my objective with the Olympics. We had a nice team plan, it was not complicated, it was simple - just to try to do our best. I saved all I had for the finish line and it worked.
"It is great to win and share the podium with great competitors. "I have a lot of respect for all the riders here. "They are both [Arndt and Vos] former world champions. It was really tactics against riders, but knowing my limit and saving my best for the end of the race. I know that would be the best I could do."