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)(11,13)(12,17)(14,15)(16,18)(19,21)(20,22)(23,24)(25,26,30,31)(27,32,35,29)(28,33,38,39)(34,40,36,37)(2,5)(6,7)(10,15)(12,20)(13,16)(19,24)(26,31)(29,32)(33,39)(37,40) involution — undirected(1,2)(3,6)(4,5)(7,8)(10,15)(11,18)(12,20)(21,23)(25,27,30,35)(26,32,31,29)(28,36,38,34)(33,37,39,40)(1,3)(2,6)(4,8)(5,7)(9,11,14,18)(10,16,15,13)(12,19,20,24)(17,23,22,21)(25,27)(26,29)(28,34)(30,35)(31,32)(33,37)(36,38)(39,40)(9,12,14,20)(10,17,15,22)(11,19,18,24)(13,21,16,23)(25,28)(26,33)(27,34)(29,37)(30,38)(31,39)(32,40)(35,36)(9,13,14,16)(10,18,15,11)(12,21,20,23)(17,24,22,19)(25,29)(26,27)(28,37)(30,32)(31,35)(33,34)(36,39)(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.