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