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