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