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