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