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