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