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