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