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