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