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