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