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