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