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