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