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