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