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