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