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