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