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