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