The Blues ran out 3-0 winners against their London rivals, taking the lead inside just three minutes through Fran Kirby.
They then missed a hatful of chances, before doubling their lead just before the hour mark as Sam Kerr scored.
The Australian nabbed a second late on as Chelsea won the delayed FA Cup final from last season to secure a domestic treble.
“I thought we got it spot-on. We predicted what they were going to do – and they did what we thought they were going to do,” said Hayes.
"We’ve painted Wembley blue, it’s certainly a Chelsea day today and our performance was absolutely superb.
"The front two were out of this world. I said to Fran it was the best game I’ve seen her play for Chelsea and Sam’s confidence is growing. But everybody played their part, did the job we asked them to do and we thoroughly deserved to be winners.
"To think we are treble winners, it is an amazing achievement – you can’t ask any more from the players and I am extremely proud of them, the staff and the club. We have built this team over a long period of time and I think today we showed why we are champions."