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