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