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