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