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