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