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