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