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