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