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