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