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