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