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