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