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