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