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