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