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