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