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