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