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