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