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