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