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