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