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