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