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