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