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