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