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