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