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