One vertex per element, one color per generator, with an edge from x to x·s.
(2,5)(6,8)(9,10)(11,16)(12,23)(13,18)(14,28)(15,20)(17,25)(19,30)(21,37)(22,35)(24,40)(26,36)(27,32)(29,34)(31,38)(33,39) involution — undirected(1,2)(3,6)(4,5)(7,8)(9,11,15,13)(10,16,20,18)(12,21,26,24)(14,27,30,22)(17,33,34,31)(19,35,28,32)(23,37,36,40)(25,39,29,38)(1,3,4,7)(2,6,5,8)(9,12)(10,17)(11,21)(13,24)(14,29)(15,26)(16,31)(18,33)(19,36)(20,34)(22,39)(23,28)(25,30)(27,38)(32,40)(35,37)(2,5)(6,8)(9,13,15,11)(10,18,20,16)(12,24,26,21)(14,22,30,27)(17,33,34,31)(19,32,28,35)(23,37,36,40)(25,38,29,39)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.