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