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