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