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