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