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