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