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