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