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