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