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)(11,17)(12,14)(13,16)(15,19)(18,24)(20,22)(21,23)(28,36)(32,37)(34,40)(38,39)(3,7)(5,8)(10,12)(15,17)(16,20)(23,24)(25,26)(27,31)(28,37)(29,33)(30,35)(32,36)(34,38)(39,40) involution — undirected(1,2)(3,5)(4,6)(7,8)(25,27)(26,30)(28,34)(29,35)(31,33)(32,38)(36,40)(37,39) involution — undirected(1,3,4,7)(2,5,6,8)(9,11)(10,15)(12,17)(13,21)(14,19)(16,24)(18,22)(20,23)(25,27)(26,31)(28,34)(29,35)(30,33)(32,39)(36,40)(37,38)(1,2)(3,5)(4,6)(7,8)(9,12,14,10)(11,17,19,15)(13,20,22,16)(18,24,21,23)(25,28)(26,32)(27,34)(29,36)(30,38)(31,39)(33,37)(35,40)(9,13,14,22)(10,16,12,20)(11,18,19,21)(15,23,17,24)(25,26)(27,30)(28,32)(29,33)(31,35)(34,38)(36,37)(39,40)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.