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