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