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