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