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