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