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