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