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