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