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