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