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