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