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