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