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