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