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