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