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