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