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