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