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