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)(25,26,31,28)(27,33,29,32)(30,34,38,36)(35,40,37,39)(1,2,5,6)(3,7,4,8)(9,11)(10,15)(12,13)(14,20)(16,24)(17,22)(18,19)(21,23)(27,29)(32,33)(35,37)(39,40)(11,20)(13,21)(15,19)(17,24)(25,27,31,29)(26,32,28,33)(30,37,38,35)(34,40,36,39)(9,10)(11,15)(12,22)(13,17)(14,18)(16,23)(19,20)(21,24)(25,28,31,26)(27,32,29,33)(30,36,38,34)(35,39,37,40)(1,3,5,4)(2,7,6,8)(9,12)(10,16)(11,21)(13,20)(14,23)(15,17)(18,22)(19,24)(25,29,31,27)(26,33,28,32)(30,37,38,35)(34,40,36,39)(1,4,5,3)(2,8,6,7)(9,13,14,21)(10,17,18,24)(11,12,20,23)(15,22,19,16)(25,30,31,38)(26,34,28,36)(27,35,29,37)(32,39,33,40)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.