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