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