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