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