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