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)(27,32)(28,36)(29,34)(30,31)(33,39)(35,40)(37,38)(1,2,5,3)(4,7,8,6)(11,15)(14,16)(18,20)(22,24)(26,31)(27,34)(33,36)(35,37)(2,3)(6,7)(9,10,12,13)(11,14,15,16)(17,18,21,20)(19,24,23,22)(25,27,30,34)(26,32,31,29)(28,37,39,35)(33,40,36,38)(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)(26,33)(27,35)(29,40)(30,39)(31,36)(32,38)(34,37)(1,4,5,8)(2,6,3,7)(9,11)(10,14)(12,15)(13,16)(17,20,21,18)(19,24,23,22)(25,29,30,32)(26,34,31,27)(28,38,39,40)(33,35,36,37)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.