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