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