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