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