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