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