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