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