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