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