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