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