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