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