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