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