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