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