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