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