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