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