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)(27,28)(29,37)(30,31)(32,35)(33,38)(34,39)(36,40)(1,3,5,8)(2,6,4,7)(9,10,14,15)(11,16,21,24)(12,17,22,20)(13,18,23,19)(26,31)(28,32)(33,37)(36,39)(10,15)(13,23)(16,24)(17,20)(25,27,30,35)(26,32,31,28)(29,34,38,40)(33,39,37,36)(1,2,5,4)(3,6,8,7)(9,11)(10,16)(12,18)(13,20)(14,21)(15,24)(17,23)(19,22)(25,27)(26,28)(29,34)(30,35)(31,32)(33,36)(37,39)(38,40)(1,4,5,2)(3,7,8,6)(9,12)(10,17)(11,19)(13,16)(14,22)(15,20)(18,21)(23,24)(25,28)(26,27)(29,36)(30,32)(31,35)(33,34)(37,40)(38,39)(9,13)(10,18)(11,20)(12,16)(14,23)(15,19)(17,21)(22,24)(25,29,30,38)(26,33,31,37)(27,34,35,40)(28,36,32,39)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.