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