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