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