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