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