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