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