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