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