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