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