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