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