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)(11,23)(12,15)(13,31)(14,19)(16,21)(17,22)(18,26)(20,34)(24,35)(25,39)(27,36)(28,29)(30,33)(32,40)(37,38) involution — undirected(1,2)(3,6)(4,5)(7,8)(9,11,15,26,17,28,16,27)(10,18,21,23,22,36,12,29)(13,32,14,25,34,38,33,24)(19,37,31,39,30,40,20,35)(2,5)(6,7)(9,12,16,22,17,21,15,10)(11,18,26,23,28,36,27,29)(13,20,33,30,34,31,14,19)(24,35,32,37,25,39,38,40)(1,3,4,8)(2,6,5,7)(9,13,15,14,17,34,16,33)(10,19,21,31,22,30,12,20)(11,24,27,38,28,25,26,32)(18,35,29,40,36,39,23,37)(9,14,16,13,17,33,15,34)(10,20,12,30,22,31,21,19)(11,25,27,32,28,24,26,38)(18,35,29,40,36,39,23,37)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.