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