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