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