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