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