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