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