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