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