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