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)(11,18)(12,21)(13,16)(14,17)(15,20)(19,23)(22,24)(25,26,31,34)(27,32,36,39)(28,29,33,30)(35,37,40,38)(1,3)(2,5)(4,7)(6,8)(9,11)(10,15)(12,19)(13,22)(14,20)(16,23)(17,18)(21,24)(25,27)(26,32)(28,35)(29,37)(30,38)(31,36)(33,40)(34,39) involution — undirected(2,6)(3,7)(25,28,30,26,31,33,29,34)(27,35,38,32,36,40,37,39)(9,12,14,13)(10,16,17,21)(11,19,20,22)(15,23,18,24)(27,36)(32,39)(35,40)(37,38)(3,7)(5,8)(9,13,14,12)(10,16,17,21)(11,19,20,22)(15,24,18,23)(25,29,31,30)(26,33,34,28)(27,37,36,38)(32,40,39,35)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.