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