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