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