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