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