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