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