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