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