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