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)(11,16)(12,18)(13,22)(14,19)(15,17)(20,23)(21,24)(26,32)(27,29)(33,39)(35,36)(1,3,5,8)(2,6,4,7)(9,11,15,20)(10,16,17,23)(12,19,22,24)(13,21,18,14)(25,26)(27,30)(28,33)(29,34)(31,32)(35,37)(36,40)(38,39)(10,17)(11,20)(12,22)(14,21)(25,27,31,29)(26,30,32,34)(28,36,38,35)(33,40,39,37)(9,12,15,22)(10,18,17,13)(11,19,20,24)(14,23,21,16)(25,28,31,38)(26,33,32,39)(27,35,29,36)(30,37,34,40)(9,13,15,18)(10,12,17,22)(11,21,20,14)(16,19,23,24)(25,29,31,27)(26,34,32,30)(28,36,38,35)(33,40,39,37)(1,4,5,2)(3,7,8,6)(9,14,15,21)(10,19,17,24)(11,18,20,13)(12,23,22,16)(25,30,31,34)(26,27,32,29)(28,37,38,40)(33,35,39,36)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.