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