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