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