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