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