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