Your realistic choices are...
Dismantle the handle and either replace the cable or shorten the existing one...
Or
Fit an in-line connector like this one...
http://www.hygienesuppliesdirect.com/images/productpics/1149041.jpg
(make sure the male pins are on the trimmer side)
Or
Throw it away and buy a new one
Peccavi
July 2009