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