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