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