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