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