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