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