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)(27,34)(28,29)(30,32)(31,35)(33,40)(36,37)(38,39) involution — undirected(1,2)(3,4)(5,6)(7,8)(10,14)(15,17)(16,20)(23,24)(25,27,31,30)(26,32,35,34)(28,38,33,36)(29,37,40,39)(2,6)(3,7)(10,14)(11,18)(16,20)(19,21)(25,28,31,33)(26,29,35,40)(27,36,30,38)(32,39,34,37)(3,7)(4,8)(9,11)(10,15)(12,21)(13,18)(14,17)(16,24)(19,22)(20,23)(25,29)(26,33)(27,37)(28,35)(30,39)(31,40)(32,36)(34,38) involution — undirected(1,3)(2,4)(5,7)(6,8)(9,10)(11,17)(12,16)(13,14)(15,18)(19,24)(20,22)(21,23)(25,27,31,30)(26,34,35,32)(28,36,33,38)(29,37,40,39)(1,4)(2,3)(5,8)(6,7)(9,12,13,22)(10,16,14,20)(11,19,18,21)(15,23,17,24)(25,30,31,27)(26,32,35,34)(28,38,33,36)(29,39,40,37)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.