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