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