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