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