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