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