One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,5)(7,8)(9,10,14,19)(11,20)(12,26,29,28)(13,15,32,16)(17,25)(18,31,36,30)(21,38)(22,23)(24,34)(27,33)(35,40)(37,39)(2,5)(6,8)(9,11,16,24,14,25,15,23)(10,17,32,34,19,20,13,22)(12,27,31,40,29,39,30,21)(18,35,28,33,36,38,26,37)(2,5)(3,7)(9,12,14,29)(10,18,19,36)(11,21,25,40)(13,28,32,26)(15,31,16,30)(17,33,20,37)(22,38,34,35)(23,27,24,39)(1,3,4,7)(2,6,5,8)(9,13,15,19,14,32,16,10)(11,22,23,20,25,34,24,17)(12,28,30,18,29,26,31,36)(21,35,39,37,40,38,27,33)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.