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