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