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