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