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