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