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