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