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