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