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