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