One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,7)(4,6)(5,8)(9,10,14,12)(11,17,19,15)(13,16,21,20)(18,23,24,22)(25,26,29,34)(27,35,37,39)(28,33,30,32)(31,38,40,36)(1,3,5,4)(2,6,8,7)(9,11,14,19)(10,15,12,17)(13,18,21,24)(16,22,20,23)(25,26)(27,31)(28,32)(29,34)(30,33)(35,36)(37,40)(38,39)(1,3,5,4)(2,7,8,6)(9,12,14,10)(11,15,19,17)(13,20,21,16)(18,22,24,23)(25,27,29,37)(26,31,34,40)(28,36,30,38)(32,35,33,39)(1,4,5,3)(2,6,8,7)(13,21)(16,20)(18,24)(22,23)(25,28,29,30)(26,32,34,33)(27,36,37,38)(31,35,40,39)(9,13,14,21)(10,16,12,20)(11,18,19,24)(15,22,17,23)(25,28,29,30)(26,33,34,32)(27,36,37,38)(31,39,40,35)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.