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