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