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