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