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)(11,15)(12,17)(13,18)(14,19)(16,20)(21,23)(22,24)(25,26)(27,32)(28,29)(30,40)(31,34)(33,38)(35,39)(36,37) involution — undirected(1,3,6,5)(2,7,4,8)(9,11)(10,15)(12,21)(13,22)(14,20)(16,19)(17,23)(18,24)(25,27,31,30)(26,32,34,40)(28,35,38,37)(29,39,33,36)(1,3,6,5)(2,7,4,8)(11,20)(15,16)(21,24)(22,23)(25,28)(26,33)(27,35)(29,34)(30,37)(31,38)(32,36)(39,40)(3,5)(7,8)(9,11)(10,16)(12,21)(13,23)(14,20)(15,19)(17,22)(18,24)(25,29,31,33)(26,28,34,38)(27,36,30,39)(32,37,40,35)(1,4,6,2)(3,8,5,7)(9,12)(10,17)(11,21)(13,19)(14,18)(15,23)(16,22)(20,24)(25,30,31,27)(26,32,34,40)(28,37,38,35)(29,39,33,36)(1,5,6,3)(2,7,4,8)(9,13,14,17)(10,18,19,12)(11,22,20,23)(15,24,16,21)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.