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