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