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