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)(26,31)(28,36)(32,34)(35,37)(2,7)(3,4)(9,10,14,18)(11,13,17,15)(12,16,20,23)(19,21,24,22)(25,26)(27,32)(28,33)(29,34)(30,31)(35,39)(36,38)(37,40)(1,3,6,4)(2,8,7,5)(9,11)(10,15)(12,19)(13,18)(14,17)(16,22)(20,24)(21,23)(25,27,30,29)(26,32,31,34)(28,35,36,37)(33,39,38,40)(1,4,6,3)(2,5,7,8)(9,11)(10,13)(12,19)(14,17)(15,18)(16,21)(20,24)(22,23)(25,28)(26,33)(27,35)(29,37)(30,36)(31,38)(32,39)(34,40)(1,5)(2,3)(4,7)(6,8)(9,12,14,20)(10,16,18,23)(11,19,17,24)(13,21,15,22)(25,26)(27,32)(28,33)(29,34)(30,31)(35,39)(36,38)(37,40)(9,13)(10,17)(11,18)(12,21)(14,15)(16,24)(19,23)(20,22)(25,29,30,27)(26,34,31,32)(28,35,36,37)(33,39,38,40)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.