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