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)(11,13)(12,16)(14,15)(17,22)(18,21)(19,23)(20,24)(25,26)(27,30)(28,35)(29,32)(31,36)(33,39)(34,38)(37,40) involution — undirected(2,5)(6,7)(10,15)(11,17)(12,19)(20,21)(25,27,29,34)(26,30,32,38)(28,33,36,40)(31,37,35,39)(1,2)(3,6)(4,5)(7,8)(10,15)(11,17)(12,19)(20,21)(25,26,29,32)(27,30,34,38)(28,31,36,35)(33,37,40,39)(1,3)(2,6)(4,8)(5,7)(9,11,14,17)(10,13,15,22)(12,18,19,24)(16,21,23,20)(25,26)(27,30)(28,31)(29,32)(33,37)(34,38)(35,36)(39,40)(9,12,14,19)(10,16,15,23)(11,18,17,24)(13,21,22,20)(25,27)(26,30)(28,33)(29,34)(31,37)(32,38)(35,39)(36,40)(9,13)(10,17)(11,15)(12,20)(14,22)(16,18)(19,21)(23,24)(25,28,29,36)(26,31,32,35)(27,33,34,40)(30,37,38,39)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.