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