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