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