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