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