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