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