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