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