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