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