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