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