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