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)(25,26,29,32)(27,30,33,37)(28,35,36,31)(34,40,39,38)(1,2,6,5)(3,8,7,4)(9,10)(11,15)(12,19)(13,14)(16,21)(17,22)(18,24)(20,23)(27,33)(30,37)(34,39)(38,40)(1,3)(2,4)(5,8)(6,7)(10,14)(15,22)(16,19)(23,24)(25,26)(27,30)(28,31)(29,32)(33,37)(34,38)(35,36)(39,40) involution — undirected(1,2,6,5)(3,4,7,8)(9,11)(10,15)(12,20)(13,17)(14,22)(16,24)(18,21)(19,23)(1,4,6,8)(2,7,5,3)(9,12)(10,16)(11,18)(13,21)(14,19)(15,23)(17,20)(22,24)(25,27)(26,30)(28,34)(29,33)(31,38)(32,37)(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)(25,28,29,36)(26,31,32,35)(27,34,33,39)(30,38,37,40)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.