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