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