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