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