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