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