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