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)(11,19)(12,23)(13,24)(14,18)(15,22)(16,21)(17,20)(26,32)(27,28)(34,39)(35,36)(2,5)(6,7)(9,11)(10,15)(12,20)(13,21)(14,22)(16,17)(18,19)(23,24)(25,26)(27,33)(28,30)(29,34)(31,32)(35,40)(36,37)(38,39) involution — undirected(1,2)(3,6)(4,5)(7,8)(25,27,31,28)(26,33,32,30)(29,35,38,36)(34,40,39,37)(1,2)(3,6)(4,5)(7,8)(9,12,14,21)(10,16,18,23)(11,20,22,13)(15,17,19,24)(25,28,31,27)(26,33,32,30)(29,36,38,35)(34,40,39,37)(1,3)(2,6)(4,8)(5,7)(9,13,14,20)(10,17,18,24)(11,21,22,12)(15,16,19,23)(25,29,31,38)(26,34,32,39)(27,35,28,36)(30,37,33,40)(9,10)(11,15)(12,23)(13,17)(14,18)(16,21)(19,22)(20,24)(25,30,31,33)(26,28,32,27)(29,37,38,40)(34,36,39,35)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.