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