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