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