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)(27,33)(28,29)(30,38)(31,32)(34,39)(35,37)(36,40)(3,7)(6,8)(9,11)(10,15)(12,18)(13,19)(14,17)(16,22)(20,24)(21,23)(26,32)(29,33)(34,38)(37,40) involution — undirected(1,2,5,4)(3,6,7,8)(11,17)(13,21)(15,18)(16,20)(25,27,31,28)(26,29,32,33)(30,36,39,35)(34,40,38,37)(9,12,14,10)(11,18,17,15)(13,16,21,20)(19,22,23,24)(25,28,31,27)(26,33,32,29)(30,36,39,35)(34,40,38,37)(1,3,5,7)(2,6,4,8)(9,13,14,21)(10,16,12,20)(11,19,17,23)(15,22,18,24)(25,29,31,33)(26,28,32,27)(30,37,39,40)(34,36,38,35)(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)(31,39)(32,38)(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.