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