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