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