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