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