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