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