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