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