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