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